Cisco IOS IP Routing: EIGRP Command Reference
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ip authentication key-chain eigrp

Table Of Contents

ip authentication key-chain eigrp

ip authentication mode eigrp

ip bandwidth-percent eigrp

ip hello-interval eigrp

ip hold-time eigrp

ip next-hop-self eigrp

ip split-horizon eigrp

ip summary-address eigrp

log-neighbor-changes (EIGRP)

log-neighbor-warnings

match extcommunity

maximum-prefix

metric holddown

metric maximum-hops

metric weights (EIGRP)

neighbor (EIGRP)

neighbor description

neighbor maximum-prefix (EIGRP)

network (EIGRP)

next-hop-self

nsf (EIGRP)

offset-list (EIGRP)

passive-interface (EIGRP)

redistribute eigrp

redistribute maximum-prefix (EIGRP)

router eigrp


ip authentication key-chain eigrp

To enable authentication of Enhanced Interior Gateway Routing Protocol (EIGRP) packets, use the ip authentication key-chain eigrp command in interface configuration mode. To disable such authentication, use the no form of this command.

ip authentication key-chain eigrp as-number key-chain

no ip authentication key-chain eigrp as-number key-chain

Syntax Description

as-number

Autonomous system number to which the authentication applies.

key-chain

Name of the authentication key chain.


Defaults

No authentication is provided for EIGRP packets.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

11.2F

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Examples

The following example applies authentication to autonomous system 2 and identifies a key chain named SPORTS:

ip authentication key-chain eigrp 2 SPORTS

Related Commands

Command
Description

accept-lifetime

Sets the time period during which the authentication key on a key chain is received as valid.

ip authentication mode eigrp

Specifies the type of authentication used in EIGRP packets.

key

Identifies an authentication key on a key chain.

key chain

Enables authentication of routing protocols.

key-string (authentication)

Specifies the authentication string for a key.

send-lifetime

Sets the time period during which an authentication key on a key chain is valid to be sent.


ip authentication mode eigrp

To specify the type of authentication used in Enhanced Interior Gateway Routing Protocol (EIGRP) packets, use the ip authentication mode eigrp command in interface configuration mode. To disable that type of authentication, use the no form of this command.

ip authentication mode eigrp as-number md5

no ip authentication mode eigrp as-number md5

Syntax Description

as-number

Autonomous system number.

md5

Keyed Message Digest 5 (MD5) authentication.


Defaults

No authentication is provided for EIGRP packets.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

11.2F

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

Configure authentication to prevent unapproved sources from introducing unauthorized or false routing messages. When authentication is configured, an MD5 keyed digest is added to each EIGRP packet in the specified autonomous system.

Examples

The following example configures the interface to use MD5 authentication in EIGRP packets in autonomous system 10:

ip authentication mode eigrp 10 md5

Related Commands

Command
Description

accept-lifetime

Sets the time period during which the authentication key on a key chain is received as valid.

ip authentication key-chain eigrp

Enables authentication of EIGRP packets.

key

Identifies an authentication key on a key chain.

key chain

Enables authentication of routing protocols.

key-string (authentication)

Specifies the authentication string for a key.

send-lifetime

Sets the time period during which an authentication key on a key chain is valid to be sent.


ip bandwidth-percent eigrp

To configure the percentage of bandwidth that may be used by Enhanced Interior Gateway Routing Protocol (EIGRP) on an interface, use the ip bandwidth-percent eigrp command in interface configuration mode. To restore the default value, use the no form of this command.

ip bandwidth-percent eigrp as-number percent

no ip bandwidth-percent eigrp as-number percent

Syntax Description

as-number

Autonomous system number.

percent

Percent of bandwidth that EIGRP may use.


Defaults

EIGRP may use 50 percent of available bandwidth.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

11.2

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

EIGRP will use up to 50 percent of the bandwidth of a link, as defined by the bandwidth interface configuration command. This command may be used if some other fraction of the bandwidth is desired. Note that values greater than 100 percent may be configured. The configuration option may be useful if the bandwidth is set artificially low for other reasons.

Examples

The following example allows EIGRP to use up to 75 percent (42 kbps) of a 56-kbps serial link in autonomous system 209:

Router(config)# interface serial 0
Router(config-if)# bandwidth 56
Router(config-if)# ip bandwidth-percent eigrp 209 75

Related Commands

Command
Description

bandwidth (interface)

Sets a bandwidth value for an interface.


ip hello-interval eigrp

To configure the hello interval for an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the ip hello-interval eigrp command in interface configuration mode. To restore the default value, use the no form of this command.

ip hello-interval eigrp as-number seconds

no ip hello-interval eigrp as-number [seconds]

Syntax Description

as-number

Autonomous system number.

seconds

Hello interval (in seconds). The range is from 1 to 65535.


Defaults

The hello interval for low-speed, nonbroadcast multiaccess (NBMA) networks is 60 seconds and 5 seconds for all other networks.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

The default of 60 seconds applies only to low-speed, NBMA media. Low speed is considered to be a rate of T1 or slower, as specified with the bandwidth interface configuration command. Note that for the purposes of EIGRP, Frame Relay and Switched Multimegabit Data Service (SMDS) networks may be considered to be NBMA. These networks are considered NBMA if the interface has not been configured to use physical multicasting; otherwise, they are considered not to be NBMA.

Examples

The following example sets the hello interval for Ethernet interface 0 to 10 seconds:

Router(config)# interface ethernet 0
Router(config-if)# ip hello-interval eigrp 109 10

Related Commands

Command
Description

bandwidth (interface)

Sets a bandwidth value for an interface.

ip hold-time eigrp

Configures the hold time for a particular EIGRP routing process designated by the autonomous system number.


ip hold-time eigrp

To configure the hold time for an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the ip hold-time eigrp command in interface configuration mode. To restore the default value, use the no form of this command.

ip hold-time eigrp as-number seconds

no ip hold-time eigrp as-number seconds

Syntax Description

as-number

Autonomous system number.

seconds

Hold time (in seconds). The range is from 1 to 65535.


Defaults

The EIGRP hold time is 180 seconds for low-speed, nonbroadcast multiaccess (NBMA) networks and 15 seconds for all other networks.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

On very congested and large networks, the default hold time might not be sufficient time for all routers and access servers to receive hello packets from their neighbors. In this case, you may want to increase the hold time.

We recommend that the hold time be at least three times the hello interval. If a router does not receive a hello packet within the specified hold time, routes through this router are considered unavailable.

Increasing the hold time delays route convergence across the network.

The default of 180 seconds hold time and 60 seconds hello interval apply only to low-speed, NBMA media. Low speed is considered to be a rate of T1 or slower, as specified with the bandwidth interface configuration command.

Examples

The following example sets the hold time for Ethernet interface 0 to 40 seconds:

Router(config)# interface ethernet 0
Router(config-if)# ip hold-time eigrp 109 40

Related Commands

Command
Description

bandwidth (interface)

Sets a bandwidth value for an interface.

ip hello-interval eigrp

Configures the hello interval for the EIGRP routing process designated by an autonomous system number.


ip next-hop-self eigrp

To instruct EIGRP that the IP next hop is itself, use the ip next-hop-self eigrp command in interface configuration mode. To instruct EIGRP to use the received next hop rather than itself, use the no form of this command.

ip next-hop-self eigrp autonomous-system-number

no ip next-hop-self eigrp autonomous-system-number

Syntax Description

autonomous-system-number

Autonomous system number.


Command Default

EIGRP always sets the IP next-hop value to be itself.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

12.3

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

EIGRP will, by default, set the IP next-hop value to be itself for routes that it is advertising, even when advertising those routes back out the same interface where it learned them. To change this default, you must use the no ip next-hop-self eigrp interface configuration command to instruct EIGRP to use the received next hop value when advertising these routes. Some exceptions to this guideline follow:

If spoke-to-spoke dynamic tunnels are not wanted, then the no ip next-hop-self eigrp command is not needed.

If spoke-to-spoke dynamic tunnels are wanted, then you must use process switching on the tunnel interface on the spoke routers. Otherwise, you will need to use a different routing protocol over Dynamic Multipoint VPN (DMVPN).

Examples

The following example changes the default IP next hop value and instructs EIGRP to use the received next hop value:

interface serial 0
 no ip next-hop-self eigrp 101 

ip split-horizon eigrp

To enable Enhanced Interior Gateway Routing Protocol (EIGRP) split horizon, use the ip split-horizon eigrp command in interface configuration mode. To disable split horizon, use the no form of this command.

ip split-horizon eigrp as-number

no ip split-horizon eigrp as-number

Syntax Description

as-number

Autonomous system number.


Defaults

The behavior of this command is enabled by default.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode.


Usage Guidelines

For networks that include links over X.25 packet-switched networks (PSNs), you can use the neighbor router configuration command to defeat the split horizon feature. As an alternative, you can explicitly specify the no ip split-horizon eigrp command in your configuration. However, if you do so, you must similarly disable split horizon for all routers and access servers in any relevant multicast groups on that network.


Note In general, we recommend that you not change the default state of split horizon unless you are certain that your application requires the change in order to properly advertise routes. Remember that if split horizon is disabled on a serial interface and that interface is attached to a packet-switched network, you must disable split horizon for all routers and access servers in any relevant multicast groups on that network.


Examples

The following example disables split horizon on a serial link connected to an X.25 network:

interface serial 0
 encapsulation x25
 no ip split-horizon eigrp 101

Related Commands

Command
Description

ip split-horizon (RIP)

Enables the split horizon mechanism.

neighbor (EIGRP)

Defines a neighboring router with which to exchange routing information.


ip summary-address eigrp

To configure a summary aggregate address for a specified interface, use the ip summary-address eigrp command in interface configuration mode. To disable a configuration, use the no form of this command.

ip summary-address eigrp as-number ip-address mask [admin-distance] [leak-map name]

no ip summary-address eigrp as-number ip-address mask

Syntax Description

as-number

Autonomous system number.

ip-address

Summary IP address to apply to an interface.

mask

Subnet mask.

admin-distance

(Optional) Administrative distance. A value from 0 to 255.

leak-map name

(Optional) Route-map reference to configure route leaking through the summary.


Defaults

An administrative distance of 5 is applied to Enhanced Interior Gateway Routing Protocol (EIGRP) summary routes.

EIGRP automatically summarizes to the network level, even for a single host route.

No summary addresses are predefined.

The default administrative distance metric for EIGRP is 90.

Command Modes

Interface configuration (config-if)
Virtual network interface (config-if-vnet)

Command History

Release
Modification

10.0

This command was introduced.

12.0(7)T

The admin-distance argument was introduced.

12.3(14)T

The leak-map keyword was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 3.2S

This command was modified. Support was added for this command in virtual network interface configuration mode. Also, the admin-distance argument is being deprecated; administrative distance is configured in the summary-metric command instead.


Usage Guidelines

The ip summary-address eigrp command is used to configure interface-level address summarization. EIGRP summary routes are given an administrative distance value of 5. The administrative distance metric is used to advertise a summary without installing it in the routing table.

By default, EIGRP summarizes subnet routes to the network level. The no auto-summary command can be entered to configure subnet level summarization.

EIGRP Support for Leaking Routes

Configuring the leak-map keyword allows to advertise a component route that would otherwise be suppressed by the manual summary. Any component subset of the summary can be leaked. A route map and access list must be defined to source the leaked route.

The following is default behavior if an incomplete configuration is entered:

If the leak-map keyword is configured to reference a nonexistent route map, the configuration of this keyword has no effect. The summary address is advertised but all component routes are suppressed.

If the leak-map keyword is configured but the access-list does not exist or the route map does not reference the access list, the summary address and all component routes are sent.

Change Beginning with Cisco IOS XE Release 3.2S

The admin-distance argument in the ip summary-address eigrp command is being deprecated, starting with Cisco IOS XE Release 3.2S. To set administrative distance, use the summary-metric command. If the admin-distance argument is configured in the ip summary-address eigrp command, the system will automatically create a summary-metric command using that same administrative distance value.

If you are configuring a virtual network trunk interface and you configure the ip summary-address eigrp command, the admin-distance value of that command is not inherited by the virtual networks running on the trunk interface because the administrative distance option is not supported in the ip summary-address eigrp command on virtual network subinterfaces.

Examples

The following example configures an administrative distance of 95 on interface Ethernet 0/0 for the 192.168.0.0/16 summary address:

Router(config)# router eigrp 1 
Router(config-router)# no auto-summary 
Router(config-router)# exit 
Router(config)# interface Ethernet 0/0 
Router(config-if)# ip summary-address eigrp 1 192.168.0.0 255.255.0.0 95 

The following example configures the 10.1.1.0/24 subnet to be leaked through the 10.0.0.0 summary address:

Router(config)# router eigrp 1 
Router(config-router)# exit 
Router(config)# access-list 1 permit 10.1.1.0 0.0.0.255 
Router(config)# route-map LEAK-10-1-1 permit 10 
Router(config-route-map)# match ip address 1 
Router(config-route-map)# exit 
Router(config)# interface Serial 0/0 
Router(config-if)# ip summary-address eigrp 1 10.0.0.0 255.0.0.0 leak-map LEAK-10-1-1 
Router(config-if)# end 

The following example configures GigabitEthernet interface 0/0/0 as a virtual network trunk interface. The system responds that the administrative distance value is accepted, but will be deprecated; use the summary-metric command to set that value.

Router(config)# interface gigabitethernet 0/0/0
Router(config-if)# vnet trunk
Router(config-if)# ip summary-address eigrp 1 1.0.0.0 255.0.0.0 33
%EIGRP: summary-address accepted but distance option deprecated; use summary-metric 
command for distance.

Related Commands

Command
Description

auto-summary (EIGRP)

Configures automatic summarization of subnet routes to network-level routes (default behavior).

summary-metric

Configures fixed metrics and administrative distance for an EIGRP summary aggregate address.


log-neighbor-changes (EIGRP)

To enable the logging of changes in Enhanced Interior Gateway Routing Protocol (EIGRP) neighbor adjacencies, use the log-neighbor-changes command in IPX-router configuration mode. To disable this function, use the no form of this command.

log-neighbor-changes

no log-neighbor-changes

Syntax Description

This command has no arguments or keywords.

Defaults

No adjacency changes are logged.

Command Modes

IPX-router configuration

Command History

Release
Modification

11.2

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.


Usage Guidelines

Enable the logging of neighbor adjacency changes in order to monitor the stability of the routing system and to help detect problems. Log messages are of the following form:

%DUAL-5-NBRCHANGE: IPX EIGRP as-number: Neighbor address (interface) is state: reason

as-number

Autonomous system number

address (interface)

Neighbor address

state

Up or down

reason

Reason for change


where the arguments have the following meanings:

Examples

The following configuration will log neighbor changes for EIGRP process 209:

ipx router eigrp 209
 log-neighbor-changes

log-neighbor-warnings


Note Effective with Cisco IOS Release 15.0(1)M, 12.2(33)SRE and Cisco IOS XE Release 2.5, the log-neighbor-warnings command was replaced by the eigrp log-neighbor-warnings command for IPv4 and IPv6 configurations. The log-neighbor-warnings command is still available for IPX configurations.


To enable the logging of Enhanced Interior Gateway Routing Protocol (EIGRP) neighbor warning messages, use the log-neighbor-warnings command in router configuration mode. To disable the logging of EIGRP neighbor warning messages, use the no form of this command.

log-neighbor-warnings [seconds]

no log-neighbor-warnings

Syntax Description

seconds

(Optional) The time interval (in seconds) between repeated neighbor warning messages. The range of seconds is from 1 through 65535.


Command Default

Neighbor warning messages are logged.

Command Modes

Router configuration (config-router)

Command History

Release
Modification

12.4(6)T

This command was introduced.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

Cisco IOS XE Release 2.1

This command was introduced on Cisco ASR 1000 Series Routers.

15.0(1)M

This command was replaced by the eigrp log-neighbor-warnings command for IPv4 and IPv6 configurations. The log-neighbor-warnings command is still available for IPX configurations.

12.2(33)SRE

This command was replaced by the eigrp log-neighbor-warnings command for IPv4 and IPv6 configurations. The log-neighbor-warnings command is still available for IPX configurations.

Cisco IOS XE Release 2.5

This command was replaced by the eigrp log-neighbor-warnings command for IPv4 and IPv6 configurations. The log-neighbor-warnings command is still available for IPX configurations.


Usage Guidelines

When neighbor warning messages occur, they are logged by default. With the log-neighbor-warnings command, you can disable and enable the logging of neighbor warning messages and configure the interval between repeated neighbor warning messages.

Examples

The following example shows that neighbor warning messages will be logged for EIGRP process 1 and warning messages will be repeated in 5-minute (300 seconds) intervals:

Router(config)# ipv6 router eigrp 1
Router(config-router)# log-neighbor-warnings 300

Related Commands

Command
Description

log-neighbor-changes

Enables the logging of changes in EIGRP neighbor adjacencies.


match extcommunity

To match Border Gateway Protocol (BGP) or Enhanced Interior Gateway Routing Protocol (EIGRP) extended community list attributes, use the match extcommunity command in route-map configuration mode. To remove the match extcommunity command from the configuration file and remove the BGP or EIGRP extended community list attribute entry, use the no form of this command.

match extcommunity extended-community-list-name

no match extcommunity extended-community-list-name

Syntax Description

extended-community-list-name

Name of an extended community list.


Command Default

BGP and EIGRP extended community list attributes are not matched.

Command Modes

Route-map configuration (config-route-map)

Command History

Release
Modification

12.1

This command was introduced.

12.0(22)S

The maximum number of expanded extended community list numbers was changed from 199 to 500 in Cisco IOS Release 12.0(22)S.

12.2(15)T

The maximum number of expanded extended community list numbers was changed from 199 to 500 in Cisco IOS Release 12.2(15)T.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. Support for EIGRP was added.

12.2(33)SRE

This command was modified. Support for EIGRP was added.

Cisco IOS XE Release 2.5

This command was modified. Support for EIGRP was added.

12.2(33)XNE

This command was modified. Support for EIGRP was added.


Usage Guidelines

Extended community attributes are used to configure, filter, and identify routes for virtual routing and forwarding instances (VRFs) and Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs).

The match extcommunity command is used to configure match clauses that use extended community attributes in route maps. All of the standard rules of match and set clauses apply to the configuration of extended community attributes.

Examples

The following example shows that the routes that match extended community list 500 will have the weight set to 100. Any route that has extended community 1 will have the weight set to 100.

Router(config)# ip extcommunity-list 500 rt 100:2
Router(config-extcomm-list)# exit
Router(config)# route-map MAP_NAME permit 10
Router(config-route-map)# match extcommunity 1
Router(config-route-map)# set weight 100

Related Commands

Command
Description

ip extcommunity-list

Creates an extended community list for BGP and controls access to it.

route-map (IP)

Defines the conditions for redistributing routes from one routing protocol into another.

set extcommunity

Sets BGP extended community attributes.

set weight

Specifies the BGP weight for the routing table.

show ip extcommunity-list

Displays routes that are permitted by the extended community list.

show route-map

Displays configured route maps.


maximum-prefix

To limit the number of prefixes that are accepted under an address family by an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the maximum-prefix command in address family configuration mode or address family topology configuration mode. To disable this function, use the no form of this command.

maximum-prefix maximum [[threshold] [dampened] [reset-time minutes] [restart minutes] [restart-count number]] | [warning-only]

no maximum-prefix

Syntax Description

maximum

Maximum number of prefixes allowed under an address family. The range for this argument is a number from 1 to 4294967295.

Note The number of prefixes that can be configured is limited only by the available system resources on the router.

threshold

(Optional) The prefix percentage number. Valid values are 1 to 100. The default is 75. This value causes the router to generate syslog warning messages when the specified percentage of the maximum-prefix limit has been exceeded.

dampened

(Optional) Configures a decay penalty to be applied to the restart-time period each time the maximum-prefix limit is exceeded. The half-life for the decay penalty is 150 percent of the default or user-defined restart-time value in minutes. This keyword is disabled by default.

reset-time minutes

(Optional) Configures the router to reset the restart count to 0 after the default or user-defined reset-time period has expired. The range of values that can be applied with the minutes argument is from 1 to 65535 minutes. The default reset-time period is 15 minutes.

restart minutes

(Optional) Configures a time period in which the router will not form adjacencies or accept redistributed routes from the Routing Information Base (RIB) after the maximum-prefix limit has been exceeded. The value for the minutes argument is from 1 to 65535 minutes. The default restart-time period is 5 minutes.

restart-count number

(Optional) Configures the number of times a peering session can be automatically reestablished after the peering session has been torn down or after a redistribute route has been cleared and relearned because the maximum-prefix limit has been exceeded. The default restart-count limit is 3.


Caution Once the restart count threshold has been crossed, you will need to enter the clear ip route * or clear ip eigrp neighbor command to reestablish normal peering and/or redistribution.

warning-only

(Optional) Configures the router to generate syslog messages only when the maximum-prefix limit is reached, instead of suspending peering session or route redistribution. This keyword is disabled by default.


Command Default

The number of prefixes that are accepted under an address family by an EIGRP process is not limited.

Command Modes

Address family configuration (config-router-af)
Address family topology configuration (config-router-af-topology)

Command History

Release
Modification

12.0(29)S

This command was introduced.

12.3(14)T

This command was integrated into Cisco IOS Release 12.3(14)T.

15.0(1)M

This command was modified. Address family topology configuration mode was added for EIGRP named configurations.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

Cisco IOS XE Release 2.6

This command was integrated into Cisco IOS XE Release 2.6.


Usage Guidelines

The maximum-prefix is used to configure an EIGRP process to limit the number prefixes that are accepted from all sources. When the maximum-prefix limit is exceeded, sessions with remote peers are torn down, all routes learned from remote peers and through redistribution are removed from the topology and routing tables, and redistribution and peering is suspended for the default or user-defined time period.

Inherited Timer Values

Default or user-defined restart, restart-count, and reset-time values for the process-level configuration of this feature, configured with the maximum-prefix command, are inherited by the redistribute maximum-prefix and neighbor maximum-prefix command configurations by default. If a single peer is configured with the neighbor maximum-prefix command, a process-level configuration or a configuration that is applied to all neighbors will be inherited.

Examples

The following example, starting in global configuration mode, configures the maximum prefix limit for an EIGRP process, which includes routes learned through redistribution and routes learned through EIGRP peering sessions. The maximum limit is set to 50000 prefixes. When the number of prefixes learned through redistribution reaches 37,500 (75 percent of 50,000), warning messages will be displayed in the console. When the maximum prefix limit is exceeded, all peering sessions will be reset, the topology and routing tables will be cleared and redistributed routes and all peering sessions will be placed in a penalty state.

Router(config)# router eigrp 100
Router(config-router)# address-family ipv4 vrf VRF1
Router(config-router-af)# maximum-prefix 50000 
Router(config-router-af)# end

The following example configures the maximum prefix limit for an EIGRP named configuration process:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# topology base
Router(config-router-af-topology)# maximum-prefix 50000 

Related Commands

Command
Description

clear ip eigrp neighbors

Deletes entries from the EIGRP neighbor table.

clear ip eigrp vrf neighbor

Deletes neighbor entries from the VRF table.

clear ip route

Deletes routes from the IP routing table.

neighbor maximum-prefix

Limits the number of prefixes that are accepted from a single EIGRP neighbor or from all EIGRP neighbors.

redistribute maximum-prefix

Limits the number of prefixes redistributed into an EIGRP process.


metric holddown

To keep new Enhanced Interior Gateway Routing Protocol (EIGRP) routing information from being used for a certain period of time, use the metric holddown command in router configuration mode. To disable this feature, use the no form of this command.

metric holddown

no metric holddown

Syntax Description

This command has no arguments or keywords.

Command Default

The holddown state is disabled.

Command Modes

Router configuration (config-router)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.


Usage Guidelines

The holddown state keeps new routing information from being used for a certain period of time. This function can prevent routing loops caused by slow convergence. It is sometimes advantageous to disable the holddown state to increase the ability of the network to quickly respond to topology changes; this command provides this function.

Use the metric holddown command if other routers or access servers within the EIGRP autonomous system are not configured with the no metric holddown command. If all routers are not configured the same way, you increase the possibility of routing loops.

Examples

The following example disables metric holddown:

Router(config)# router eigrp 15
Router(config-router)# network 172.16.0.0
Router(config-router)# network 192.168.7.0
Router(config-router)# no metric holddown

Related Commands

Command
Description

metric maximum-hops

Causes the IP routing software to advertise as unreachable those routes with a hop count higher than is specified by the command (EIGRP only).

metric weights (EIGRP)

Allows the tuning of the EIGRP metric calculations.


metric maximum-hops

To have the IP routing software advertise as unreachable routes with a hop count higher than is specified by the command (Enhanced Interior Gateway Routing Protocol [EIGRP] only), use the metric maximum-hops command in router configuration mode or address family topology configuration mode. To reset the value to the default, use the no form of this command.

metric maximum-hops hops-number

no metric maximum-hops

Syntax Description

hops-number

Maximum hop count (in decimal). The default value is 100; the maximum number of hops that can be specified is 255.


Command Default

The maximum number of hops is 100.

Command Modes

Router configuration (config-router)
Address family topology configuration (config-router-af-topology)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

15.0(1)M

This command was modified. The address-family topology configuration mode was added.

12.2(33)SRE

This command was modified. The address-family topology configuration mode was added.

Cisco IOS XE Release 2.5

This command was modified. The address-family topology configuration mode was added.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

This command provides a safety mechanism that breaks any potential count-to-infinity problems. It causes the IP routing software to advertise as unreachable routes with a hop count greater than the value assigned to the hops-number argument.

Examples

In the following example, a router in autonomous system 71 attached to network 10.0.0.0 wants a maximum hop count of 200, doubling the default. The network administrators configured the router hop count to 200 because they have a complex WAN that can generate a large hop count under normal (nonlooping) operations.

Router(config)# router eigrp 71
Router(config-router)# network 172.16.0.0
Router(config-router)# metric maximum-hops 200

The following example shows how to configure EIGRP autonomous-system 4453 to have a maximum hop count of 200:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# topology base
Router(config-router-af-topology)# metric maximum-hops 200

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

metric holddown

Keeps new EIGRP routing information from being used for a certain period of time.

metric weights (EIGRP)

Allows the tuning of the EIGRP metric calculations.

network (EIGRP)

Specifies the network for an EIGRP routing process.

router eigrp

Configures the EIGRP address-family process.

topology (EIGRP)

Configures an EIGRP process to route IP traffic under the specified topology instance and enters address-family topology configuration mode.


metric weights (EIGRP)

To tune Enhanced Interior Gateway Routing Protocol (EIGRP) metric calculations, use the metric weights command in router configuration mode or address family configuration mode. To reset the values to their defaults, use the no form of this command.

metric weights tos k1 k2 k3 k4 k5

no metric weights

Syntax Description

tos

Type of service. This value must always be zero.

k1 k2 k3 k4 k5

Constants that convert an EIGRP metric vector into a scalar quantity. Valid values are 0 to 255. Default values are:

tos: 0

k1: 1

k2: 0

k3: 1

k4: 0

k5: 0


Command Default

EIGRP metric K values are set to their default values.

Command Modes

Router configuration (config-router)
Address family configuration (config-router-af)

Command History

Release
Modification

10.0

This command was introduced.

12.4(6)T

Support for IPv6 was added.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. The address-family configuration mode was added.

12.2(33)SRE

This command was modified. The address-family configuration mode was added.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 2.5

This command was modified. The address-family configuration mode was added.


Usage Guidelines

Use this command to alter the default behavior of EIGRP routing and metric computation and allow the tuning of the EIGRP metric calculation for a particular type of service (ToS).

If k5 equals 0, the composite EIGRP metric is computed according to the following formula:

metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay]

If k5 does not equal zero, an additional operation is performed:

metric = metric * [k5/(reliability + k4)]

Bandwidth is inverse minimum bandwidth of the path in bps scaled by a factor of 2.56 * 1012. The range is from a 1200-bps line to 10 terabits per second.

Delay is in units of 10 microseconds. The range of delay is from 10 microseconds to 168 seconds. A delay of all ones indicates that the network is unreachable.

The delay parameter is stored in a 32-bit field, in increments of 39.1 nanoseconds. The range of delay is from 1 (39.1 nanoseconds) to hexadecimal FFFFFFFF (decimal 4,294,967,040 nanoseconds). A delay of all ones (that is, a delay of hexadecimal FFFFFFFF) indicates that the network is unreachable.

Table 2 lists the default values used for several common media.

Table 2 Bandwidth Values by Media Type 

Media Type
Delay
Bandwidth

Satellite

51,200,000 (2 seconds)

5120 (500 megabits)

Ethernet

25600 (1 millisecond [ms])

256,000 (10 megabits)

1.544 Mbps

51,200,000 (20 ms)

1,657,856 bits

64 kbps

51,200,000 (20 ms)

40,000,000 bits

56 kbps

51,200,000 (20 ms)

45,714,176 bits

10 kbps

51,20,000 (20 ms)

256,000,000 bits

1 kbps

51,200,000 (20 ms)

2,560,000,000 bits


Reliability is given as a fraction of 255. That is, 255 is 100 percent reliability or a perfectly stable link.

Load is given as a fraction of 255. A load of 255 indicates a completely saturated link.

Examples

The following example sets the metric weights to slightly different values than the defaults:

Router(config)# router eigrp 109
Router(config-router)# network 192.168.0.0
Router(config-router)# metric weights 0 2 0 2 0 0

The following example configures an address-family metric weight to tos: 0; K1: 2; K2: 0; K3: 2; K4: 0; K5: 0.

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4533
Router(config-router-af)# metric weights 0 2 0 2 0 0

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

bandwidth (interface)

Sets a bandwidth value for an interface.

delay (interface)

Sets a delay value for an interface.

ipv6 router eigrp

Configures the EIGRP for IPv6 routing process.

metric holddown

Keeps new EIGRP routing information from being used for a certain period of time.

metric maximum-hops

Causes the IP routing software advertise as unreachable routes with a hop count higher than is specified by the command (EIGRP only).

router eigrp

Configures the EIGRP address-family process.


neighbor (EIGRP)

To define a neighboring router with which to exchange routing information on a router that is running Enhanced Interior Gateway Routing Protocol (EIGRP), use the neighbor command in router configuration mode or address-family configuration mode. To remove an entry, use the no form of this command.

neighbor {ip-address | ipv6-address} interface-type interface-number [remote maximum-hops]

no neighbor {ip-address | ipv6-address} interface-type interface-number

Syntax Description

ip-address

IP address of a peer router with which routing information will be exchanged.

ipv6-address

IPv6 address of a peer router with which routing information will be exchanged.

interface-type

Interface through which peering is established.

interface-number

Number of the interface or subinterface.

remote

(Optional) Specifies that the neighbor is remote. This keyword is available only for loopback interfaces.

maximum-hops

(Optional) Maximum hop count. Valid range is 3 to 100. This argument is available only when the remote keyword is configured.


Command Default

No neighboring routers are defined.

Command Modes

Router configuration (config-router)
Address-family configuration (config-router-af)

Command History

Release
Modification

10.0

This command was introduced.

12.4(6)T

The ipv6-address argument was added.

12.2(33)SRB

This command was integrated into Cisco IOS Release 12.2(33)SRB.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. Address-family configuration mode was added.

12.2(33)SRE

This command was modified. Address-family configuration mode was added.

Cisco IOS XE Release 2.5.

This command was modified. Address-family configuration mode was added.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

Multiple neighbor statements can be used to establish peering sessions with specific EIGRP neighbors. The interface through which EIGRP will exchange routing updates must be specified in the neighbor statement. The interfaces through which two EIGRP neighbors exchange routing updates must be configured with IP addresses from the same network.


Note Configuring the passive-interface command suppresses all incoming and outgoing routing updates and hello messages. EIGRP neighbor adjacencies cannot be established or maintained over an interface that is configured as passive.


Examples

The following example configures EIGRP peering sessions with the 192.168.1.1 and 192.168.2.2 neighbors:

Router(config)# router eigrp 1
Router(config-router)# network 192.168.0.0
Router(config-router)# neighbor 192.168.1.1 Ethernet 0/0
Router(config-router)# neighbor 192.168.2.2 Ethernet 1/1

The following named configuration example configures EIGRP to send address-family updates to specific neighbors:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# neighbor 192.168.1.1 ethernet0/0
Router(config-router-af)# neighbor 10.1.1.2 loopback0 remote 10

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

ipv6 router eigrp

Configures the EIGRP for IPv6 routing process.

passive-interface

Disables sending EIGRP hello packets and disables routing updates on an interface.

router eigrp

Configures the EIGRP address-family process.


neighbor description

To associate a description with a neighbor, use the neighbor description command in router configuration mode or address family configuration mode. To remove the description, use the no form of this command.

neighbor {ip-address | peer-group-name} description text

no neighbor {ip-address | peer-group-name} description [text]

Syntax Description

ip-address

IP address of the neighbor.

peer-group-name

Name of an EIGRP peer group. This argument is not available in address-family configuration mode.

text

Text (up to 80 characters in length) that describes the neighbor.


Command Default

There is no description of the neighbor.

Command Modes

Router configuration (config-router)
Address family configuration (config-router-af)

Command History

Release
Modification

11.3

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. Address-family configuration mode was added.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

Cisco IOS XE Release 2.6

This command was integrated into Cisco IOS XE Release 2.6.


Examples

In the following examples, the description of the neighbor is "peer with example.com":

Router(config)# router bgp 109
Router(config-router)# network 172.16.0.0
Router(config-router)# neighbor 172.16.2.3 description peer with example.com

In the following example, the description of the address family neighbor is "address-family-peer":

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# network 172.16.0.0
Router(config-router-af)# neighbor 172.16.2.3 description address-family-peer

Related Commands

Command
Description

address-family (EIGRP)

Enters address family configuration mode to configure an EIGRP routing instance.

network (EIGRP)

Specifies the network for an EIGRP routing process.

router eigrp

Configures the EIGRP address family process.


neighbor maximum-prefix (EIGRP)

To limit the number of prefixes that are accepted from a single Enhanced Interior Gateway Protocol (EIGRP) neighbor or from all EIGRP neighbors, use the neighbor maximum-prefix command in address family configuration mode. To disable this function, use the no form of this command.

Single Neighbor Configuration

neighbor ip-address maximum-prefix maximum [threshold] [warning-only]

no neighbor ip-address maximum-prefix

All Neighbor Configuration

neighbor maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count number] | warning-only]

no neighbor maximum-prefix

Syntax Description

ip-address

IP address of a single peer.

maximum

Maximum number of prefixes accepted. The range for this argument is a number from 1 to 4294967295.

Note The number of prefixes that can be configured is limited only by the available system resources on the router.

threshold

(Optional) Configures the router to generate syslog warning messages when the specified percentage of the maximum-prefix limit has been reached. The prefix percentage number that can be configured for the threshold argument is from 1 to 100. The default is 75 percent.

warning-only

(Optional) Configures the router to generate syslog messages only when the maximum-prefix limit is reached, instead of terminating the peering session. This keyword is disabled by default.

dampened

(Optional) Configures a decay penalty to be applied to the restart-time period each time the maximum-prefix limit is reached. The half-life for the decay penalty is 150 percent of the default or user-defined restart-time value in minutes. This keyword is disabled by default.

reset-time minutes

(Optional) Configures the router to reset the restart count to 0 after the default or configured reset-time period has expired. The value for the minutes argument is from 1 to 65535 minutes. The default reset-time period is 15 minutes.

restart minutes

(Optional) Configures a time period in which the router will not form adjacencies or accept redistributed routes from the RIB after the maximum-prefix limit has been reached. The value for the minutes argument is from 1 to 65535 minutes. The default restart-time period is 5 minutes.

restart-count number

(Optional) Configures the number of times a peering session can be automatically reestablished after the peering session has been torn down or after a redistribute route has been cleared and relearned because the maximum-prefix limit has been reached. The default restart-count limit is 3.


Caution Once the restart count threshold has been crossed, you will need to enter the clear ip route * or clear ip eigrp neighbor command to reestablish normal peering and/or redistribution.

Command Default

The number of prefixes that can be configured is limited only by the available system resources on the router.

Command Modes

Address family configuration (config-router-af)

Command History

Release
Modification

12.0(29)S

This command was introduced.

12.3(14)T

This command was integrated into Cisco IOS Release 12.3(14)T.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

Cisco IOS XE Release 2.6

This command was integrated into Cisco IOS XE Release 2.6.


Usage Guidelines

The neighbor maximum-prefix command can be configured to protect an individual peering session or to protect all peering sessions. When this feature is enabled and the maximum-prefix limit has been reached, the router will tear down the peering session, clear all routes that were learned from the peer, and then place the peer in a penalty state for the default or user-defined time period. After the penalty time period expires, normal peering will be reestablished.


Note In EIGRP, neighbor commands have been traditionally used to configure static neighbors. In the context of the EIGRP Prefix Limiting feature, however, the neighbor maximum-prefix command can be used to configure the maximum-prefix limit for both statically configured neighbors and dynamically discovered neighbors.


When you configure the neighbor maximum-prefix command to protect a single peering session, only the maximum-prefix limit, the percentage threshold, and the warning-only configuration options can be configured. Session dampening, restart, and reset timers are configured on a global basis.

Inherited Timer Values

Default or user-defined restart, restart-count, and reset-time values for the process-level configuration of this feature, configured with the maximum-prefix command, are inherited by the redistribute maximum-prefix and neighbor maximum-prefix command configurations by default. If a single peer is configured with the neighbor maximum-prefix command, a process-level configuration or a configuration that is applied to all neighbors will be inherited.

Examples

Configuring the Maximum Prefix Limit for a Single Peer

The following example, starting in global configuration mode, configures the maximum prefix limit for a single peer. The maximum limit is set to 1000 prefixes, and the warning threshold is set to 80 percent. When the maximum prefix limit is reached for the configured neighbor, adjacency with this neighbor will be brought down and all routes learned from it will be cleared. The neighbor will be placed in a penalty state for 4 minutes (user-defined penalty value). This function will not affect the relationship with any other neighbor.

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# neighbor 10.0.0.1 maximum-prefix 1000 80 
Router(config-router-af)# end

Configuring the Maximum Prefix Limit for All Peers

The following example, starting in global configuration mode, configures the maximum prefix limit for all peers. The maximum limit is set to 10,000 prefixes, the warning threshold is set to 90 percent, the restart timer is set to 4 minutes, a decay penalty is configured for the restart timer with the dampened keyword, and all timers are configured to be reset to 0 every 60 minutes. When the maximum prefix limit is reached for any neighbor, adjacency with this neighbor will be brought down and all routes learned from it will be cleared. This function will not affect the relationship with any other neighbor. The offending peer will be placed in a penalty state for 4 minutes (user-defined penalty value). A dampening exponential decay penalty will also be applied.

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 virtual-name autonomous-system 4453
Router(config-router-af)# neighbor maximum-prefix 10000 90 dampened reset-time 60 
restart 4
Router(config-router-af)# end 

Related Commands

Command
Description

address-family (EIGRP)

Enters address family configuration mode to configure an EIGRP routing instance.

clear ip eigrp neighbors

Deletes entries from the EIGRP neighbor table.

clear ip eigrp vrf neighbor

Deletes neighbor entries from the VRF table.

clear ip route

Deletes routes from the IP routing table.

neighbor maximum-prefix

Limits the number of prefixes that are accepted from a single EIGRP neighbor or from all EIGRP neighbors.

redistribute maximum-prefix (EIGRP)

Limits the number of prefixes redistributed into an EIGRP process.


network (EIGRP)

To specify the network for an Enhanced Interior Gateway Routing Protocol (EIGRP) routing process, use the network command in router configuration mode or address-family configuration mode. To remove an entry, use the no form of this command.

network ip-address [wildcard-mask]

no network ip-address [wildcard-mask]

Syntax Description

ip-address

IP address of the directly connected network.

wildcard-mask

(Optional) Wildcard mask.


Command Default

No networks are specified.

Command Modes

Router configuration (config-router)
Address-family configuration (config-router-af)

Command History

Release
Modification

10.0

This command was introduced.

12.0(4)T

The network-mask argument was added.

12.0(22)S

Address-family support for EIGRP was added.

12.2(15)T

Address-family support for EIGRP was added.

12.2(18)S

Address-family support for EIGRP was added.

12.2(27)SBC

This command was integrated into Cisco IOS Release 12.2(27)SBC.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.


Usage Guidelines

When the network command is configured for an EIGRP routing process, the router matches one or more local interfaces. The network command matches only local interfaces that are configured with addresses that are within the same subnet as the address that has been configured with the network command. The router then establishes neighbors through the matched interfaces. There is no limit to the number of network statements (network commands) that can be configured on a router.

When entered in address-family configuration mode, this command applies only to named EIGRP IPv4 configurations. Named IPv6 and Service Advertisement Framework (SAF) configurations do not support this command in address-family configuration mode.

Examples

The following example configures EIGRP autonomous system 1 and establishes neighbors through network 172.16.0.0 and 192.168.0.0:

Router(config)# router eigrp 1 
Router(config-router)# network 172.16.0.0
Router(config-router)# network 192.168.0.0

The following example configures EIGRP address-family autonomous system 4453 and establishes neighbors through network 172.16.0.0 and 192.168.0.0:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# network 172.16.0.0
Router(config-router-af)# network 192.168.0.0

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

router eigrp

Configures the EIGRP address-family process.



next-hop-self

To enable Enhanced Interior Gateway Routing Protocol (EIGRP) to advertise routes with the local outbound interface address as the next hop, use the next-hop-self command in address-family interface configuration mode. To instruct an EIGRP router to use the received next hop rather than the local outbound interface address, use the no form of this command.

next-hop-self

no next-hop-self

Syntax Description

This command has no arguments or keywords.

Command Default

The next-hop-self state is enabled, causing EIGRP to use a local address in the next-hop field of its routing advertisements.

Command Modes

Address-family interface (config-router-af-interface)

Command History

Release
Modification

15.0(1)M

This command was introduced.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 2.5

This command was integrated into Cisco IOS XE Release 2.5.


Usage Guidelines

The next-hop-self command is an interface-based command. EIGRP will, by default, set the next-hop value to the local outbound interface address for routes that it is advertising, even when advertising those routes back out the same interface where it learned them. To change this default, you must use the no next-hop-self command to instruct EIGRP to use the received next hop value when advertising these routes. Disabling next-hop-self is primarily useful in Dynamic Multipoint VPN (DMVPN) spoke-to-spoke topologies.

Examples

The following example changes the default next-hop value and instructs EIGRP to use the received next-hop address in its routing advertisements:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 33
Router(config-router-af)# af-interface ethernet0/0
Router(config-router-af-interface)# no next-hop-self

nsf (EIGRP)

To enable Cisco nonstop forwarding (NSF) operations for Enhanced Interior Gateway Protocol (EIGRP), use the nsf command in router configuration mode or address-family configuration mode. To disable EIGRP NSF and remove the EIGRP NSF configuration from the running-config file, use the no form of this command.

nsf

no nsf

Syntax Description

This command has no arguments or keywords.

Command Default

EIGRP NSF capability is enabled by default.

Command Modes

Router configuration (config-router)
Address-family configuration (config-router-af)

Command History

Release
Modification

12.2(18)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXH

This command was integrated into Cisco IOS Release 12.2(33)SXH.

15.0(1)M

This command was modified. Address-family configuration mode was added.

12.2(33)SRE

This command was modified. Address-family configuration mode was added.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 2.5

This command was integrated into Cisco IOS XE Release 2.5.


Usage Guidelines

This command is used to enable or disable EIGRP NSF support on an NSF capable router. EIGRP NSF capability is enabled by default on distributed platforms that run a supporting version of Cisco IOS software.

Examples

The nsf command is used to enable or disable the EIGRP NSF capability. The following example disables NSF capability:

Router# configure terminal
Router(config)# router eigrp 101 
Router(config-router)# no nsf 

The nsf command is used to enable or disable the EIGRP NSF capability. The following EIGRP named configuration example disables NSF capability:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 as 10 
Router(config-router-af)# no nsf 

Related Commands

Command
Description

debug eigrp nsf

Displays notifications and information about NSF events for an EIGRP routing process.

debug ip eigrp notifications

Displays information and notifications for an EIGRP routing process. This output includes NSF notifications and events.

show ip protocols

Displays the parameters and current state of the active routing protocol process. The status of EIGRP NSF configuration and support is displayed in the output.

timers nsf converge

Adjusts the maximum time that restarting router will wait for the EOT notification from an NSF-capable or NSF-aware peer.

timers nsf route-hold

Adjusts the maximum period of time that a supporting peer will hold known routes for an NSF-capable router during a restart operation or during a well-known failure condition.

timers nsf signal

Adjusts the maximum time for the initial restart period.


offset-list (EIGRP)

To add an offset to incoming and outgoing metrics to routes learned via Enhanced Interior Gateway Routing Protocol (EIGRP), use the offset-list command in router configuration mode or address family topology configuration mode. To remove an offset list, use the no form of this command.

offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

no offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

Syntax Description

access-list-number | access-list-name

Standard access list number or name to be applied. Access list number 0 indicates all networks (networks, prefixes, or routes). If the offset value is 0, no action is taken.

in

Applies the access list to incoming metrics.

out

Applies the access list to outgoing metrics.

offset

Positive offset to be applied to metrics for networks matching the access list. If the offset is 0, no action is taken.

interface-type

(Optional) Interface type to which the offset list is applied.

interface-number

(Optional) Interface number to which the offset list is applied.


Command Default

No offset values are added to incoming or outgoing metrics to routes learned via EIGRP.

Command Modes

Router configuration (config-router)
Address family topology configuration (config-router-af-topology)

Command History

Release
Modification

10.0

This command was introduced.

10.3

The interface-type and interface-number arguments were added.

11.2

The access-list-name argument was added.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. The address family configuration mode was added.

12.2(33)SRE

This command was modified. The address family configuration mode was added.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 2.5

This command was modified. The address family configuration mode was added.


Usage Guidelines

The offset value is added to the routing metric. An offset list with an interface type and interface number is considered extended and takes precedence over an offset list that is not extended. Therefore, if an entry passes the extended offset list and the normal offset list, the offset of the extended offset list is added to the metric.

Examples

In the following example, the router applies an offset of 10 to the delay component of the router only to access list 21:

Router(config-router)# offset-list 21 out 10

In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:

Router(config-router)# offset-list 21 in 10 ethernet 0

In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0 in an EIGRP named configuration:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 1
Router(config-router-af)# topology base
Router(config-router-af-topology)# offset-list 21 in 10 ethernet0

passive-interface (EIGRP)

To suppress Enhanced Interior Gateway Routing Protocol (EIGRP) hello packets and routing updates on interfaces while still including the interface addresses in the topology database, use the passive-interface command in router configuration mode, address-family configuration mode, or address-family interface configuration mode. To reenable outgoing hello packets and routing updates, use the no form of this command.

passive-interface [default] [interface-type interface-number]

no passive-interface [default] [interface-type interface-number]

Syntax Description

default

(Optional) Configures all interfaces as passive.

interface-type

(Optional) Interface type. For more information, use the question mark (?) online help function.

interface-number

(Optional) Interface or subinterface number. For more information about the numbering syntax for your networking device, use the question mark (?) online help function.


Command Default

Hello packets and routing updates are sent and received on the interface.

Command Modes

Router configuration (config-router)
Address-family configuration (config-router-af)
Address-family interface configuration (config-router-af-interface)

Command History

Release
Modification

15.0(1)M

This command was introduced.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

12.2(33)XNE

This command was integrated into Cisco IOS Release 12.2(33)XNE.

Cisco IOS XE Release 2.5

This command was integrated into Cisco IOS XE Release 2.5.


Usage Guidelines

Use the passive-interface (EIGRP) command to select interfaces that will not form EIGRP neighbor adjacencies yet include the interface addresses in the EIGRP topology database. When the passive-interface (EIGRP) command is configured, networks defined on the interface are added to the EIGRP topology database while routing updates and hello packets over the passive interfaces are suppressed.

The default keyword sets all interfaces to passive. Individual interfaces can be specified to override the default passive-interface state by using the no passive-interface command. The default keyword is useful when there are more passive interfaces than active interfaces. If the default keyword is not specified, the interfaces are considered nonpassive.

Examples

The following example shows how to place the router in the router configuration mode and set all EIGRP interfaces to the passive state and then set Ethernet interface 0/0 to a nonpassive state:

Router(config)# router eigrp 109
Router(config-router)# passive-interface default
Router(config-router)# no passive-interface ethernet0/0

The following example shows how to place the router in the address-family configuration mode and set all EIGRP interfaces in VRF RED to the passive state and then set Ethernet interface 0/0 to a nonpassive state:

Router(config)# router eigrp 109
Router(config-router)# address-family ipv4 vrf RED
Router(config-router-af)# passive-interface default
Router(config-router-af)# no passive-interface ethernet0/0 

The following EIGRP named address-family interface configuration example sets all interfaces in an address family to passive and then sets Ethernet 0/0 to a nonpassive state:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 autonomous-system 4453
Router(config-router-af)# af-interface default
Router(config-router-af-interface)# passive-interface
Router(config-router-af-interface)# exit
Router(config-router-af)# af-interface ethernet0/0
Router(config-router-af-interface)# no passive-interface

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

af-interface

Enters address-family interface configuration mode to configure interface-specific EIGRP commands.

network (EIGRP)

Specifies the network for an EIGRP routing process.

router eigrp

Configures the EIGRP address-family process.


redistribute eigrp

To redistribute IPv4 routes from Enhanced Interior Gateway Routing Protocol (EIGRP), use the redistribute eigrp command in router configuration mode. To disable the configuration, use the no form of this command.

redistribute eigrp system-number [metric bandwidth-metric delay-metric reliability-metric effective-bandwidth-metric mtu-bytes] [route-map pointer-name]

no redistribute eigrp system-number [metric [bandwidth-metric delay-metric reliability-metric effective-bandwidth-metric mtu-bytes | route-map pointer-name]

Syntax Description

system-number

Autonomous system number. The range is from 1 to 65535.

metric

(Optional) Specifies the metric for redistributed routes.

bandwidth-metric

(Optional) Maximum bandwidth of the route, in kilobits per second (kb/s). The range is from 1 to 4294967295.

delay-metric

(Optional) EIGRP route delay metric, in microseconds. The range is from 1 to 4294967295.

reliability-metric

(Optional) EIGRP reliability metric. The range is from 0 to 255.

An EIGRP metric of 255 signifies 100 percent reliability.

effective-bandwidth-
metric

(Optional) Effective bandwidth of the route. The range is from 1 to 255.

Effective bandwidth of 255 denotes 100 percent load.

mtu-bytes

(Optional) The smallest allowed value for the maximum transmission unit (MTU), in bytes. The range is from 1 to 65535.

route-map

(Optional) Specifies the route map reference.

pointer-name

(Optional) Pointer to route-map entries.


Command Default

Route redistribution is disabled.

Command Modes

Router configuration (config-router)

Command History

Release
Modification

12.2(8)T

This command was introduced in a release earlier than Cisco IOS Release 12.2(8)T.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(33)SXI

This command was integrated into Cisco IOS Release 12.2(33)SXI.

Cisco IOS XE Release 2.1

This command was implemented on the Cisco ASR 1000 Series Aggregation Services Routers.


Usage Guidelines

Use the redistribute eigrp command to redistribute the routes learned through the EIGRP routing instances to other routing protocols. Forward redistribution of the EIGRP routes is allowed before creating the EIGRP routing instance. The EIGRP redistribution takes place as soon as the routing instance is created.

The metric value specified in the redistribute command supersedes the metric value specified using the default-metric command.


Note In Cisco IOS Release 12.0(33)S, the redistribution eigrp command is not allowed if the EIGRP router is not defined. The command terminates by displaying the following error message:
%Configure eigrp router mode before redistributing


Examples

The following example shows how to configure a router to redistribute EIGRP routes into an EIGRP process:

Router# configure terminal 
Router(config)# router eigrp virtual-name
Router(config-router)# redistribute eigrp 6473 metric 1 2 3 4 5

The following example shows the behavior of the redistribution eigrp command when the EIGRP router is not defined in Cisco IOS Release 12.0(33)S:

Router# configure terminal
Router(config)# router ospf 100 vrf vrf1
Router(config-router)# redistribute eigrp 99
%Configure eigrp router mode before redistributing

Related Commands

Command
Description

default-metric

Sets metrics for EIGRP.


redistribute maximum-prefix (EIGRP)

To limit the number of prefixes redistributed into an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the redistribute maximum-prefix command in address family configuration mode or address-family topology configuration mode. To disable this function, use the no form of this command.

redistribute maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count number] | [warning-only]]

no redistribute maximum-prefix

Syntax Description

maximum

Maximum number of prefixes that are redistributed into EIGRP under an address family. The range for this argument is a number from 1 to 4294967295.

Note The number of prefixes that can be configured is limited only by the available system resources on the router.

threshold

(Optional) The prefix percentage number. Valid values are 1 to 100. The default is 75. This value causes the router to generate syslog warning messages when the specified percentage of the maximum-prefix limit has been exceeded.

dampened

(Optional) Configures a decay penalty to be applied to the restart-time period each time the maximum-prefix limit is exceeded. The half-life for the decay penalty is 150 percent of the default or user-defined restart-time value in minutes. This keyword is disabled by default.

reset-time minutes

(Optional) Configures the router to reset the restart count to 0 after the default or configured reset-time period has expired. The value for the minutes argument is from 1 to 65535 minutes. The default reset-time period is 15 minutes.

restart minutes

(Optional) Configures a time period in which the router will not form adjacencies or accept redistributed routes from the Routing Information Base (RIB) after the maximum-prefix limit has been exceeded. The value for the minutes argument is from 1 to 65535 minutes. The default restart-time period is 5 minutes.

restart-count number

(Optional) Configures the number of times a peering session can be automatically be reestablished after the peering session has been torn down or after a redistribute route has been cleared and relearned because the maximum-prefix limit has been exceeded. The default restart-count limit is 3.


Caution Once the restart count threshold has been crossed, you will need to enter the clear ip route * or clear ip eigrp neighbor command to reestablish normal peering and/or redistribution.

warning-only

(Optional) Configures the router to generate syslog messages only when the maximum-prefix limit is reached, instead of suspending redistribution. This keyword is disabled by default.


Command Default

The number of prefixes redistributed into an EIGRP process is not limited.

Command Modes

Address family configuration (config-router-af)
Address family topology configuration (config-router-af-topology)

Command History

Release
Modification

12.0(29)S

This command was introduced.

12.3(14)T

This command was integrated into Cisco IOS Release 12.3(14)T.

15.0(1)M

This command was modified. Address family topology configuration mode was added.

12.2(33)SRE

This command was integrated into Cisco IOS Release 12.2(33)SRE.

Cisco IOS XE Release 2.6

This command was integrated into Cisco IOS XE Release 2.6.


Usage Guidelines

The redistribute maximum-prefix command is used to configure limit prefixes learned through redistribution. When the maximum-prefix limit is exceeded, all routes learned from the RIB will be discarded and redistribution will be suspended for the default or user-defined time period. The maximum-prefix limit that can be configured for redistributed prefixes is limited only by the available system resources on the router.

Inherited Timer Values

Default or user-defined restart, restart-count, and reset-time values for the process-level configuration of this feature, configured with the maximum-prefix command, are inherited by the redistribute maximum-prefix (EIGRP) and neighbor maximum-prefix (EIGRP) command configurations by default. If a single peer is configured with the neighbor maximum-prefix (EIGRP) command, a process-level configuration or a configuration that is applied to all neighbors will be inherited.

Examples

The following example, starting in global configuration mode, configures the maximum prefix limit for routes learned through redistribution. The maximum limit is set to 5000 prefixes and the warning threshold is set to 95 percent. When the number of prefixes learned through redistribution reaches 4750 (95 percent of 5000), warning messages will be displayed in the console. Because the warning-only keyword was configured, the topology and routing tables will not be cleared and route redistribution will not be placed in a penalty state.

Router(config)# router eigrp 100
Router(config-router)# address-family ipv4 vrf RED
Router(config-router-af)# redistribute maximum-prefix 5000 95 warning-only 
Router(config-router-af)# end

The following example shows this configuration in address-family topology configuration mode:

Router(config)# router eigrp virtual-name
Router(config-router)# address-family ipv4 vrf RED autonomous-system 4453
Router(config-router-af)# network 172.16.0.0
Router(config-router-af)# topology base
Router(config-router-af-topology)# redistribute maximum-prefix 5000 95 warning-only 
Router(config-router-af-topology)# exit-af-topology

Related Commands

Command
Description

address-family (EIGRP)

Enters address-family configuration mode to configure an EIGRP routing instance.

clear ip eigrp neighbors

Deletes entries from the EIGRP neighbor table.

clear ip eigrp vrf neighbor

Deletes neighbor entries from the VRF table.

clear ip route

Deletes routes from the IP routing table.

network (EIGRP)

Specifies the network for an EIGRP routing process.

redistribute maximum-prefix (EIGRP)

Limits the number of prefixes redistributed into an EIGRP process.

topology (EIGRP)

Configures an EIGRP process to route IP traffic under the specified topology instance and enters address-family topology configuration mode.


router eigrp

To configure the Enhanced Interior Gateway Routing Protocol (EIGRP) routing process, use the router eigrp command in global configuration mode. To remove an EIGRP routing process, use the no form of this command.

router eigrp {autonomous-system-number | virtual-instance-name}

no router eigrp {autonomous-system-number | virtual-instance-name}

Syntax Description

autonomous-system-number

Autonomous system number that identifies the services to the other EIGRP address-family routers. It is also used to tag routing information. Valid range is 1 to 65535.

virtual-instance-name

EIGRP virtual instance name. This name must be unique among all address-family router processes on a single router, but need not be unique among routers.


Command Default

No EIGRP processes are configured.

Command Modes

Global configuration (config)

Command History

Release
Modification

10.0

This command was introduced.

12.2(33)SRA

This command was integrated into Cisco IOS Release 12.2(33)SRA.

12.2(31)SB2

This command was integrated into Cisco IOS Release 12.2(31)SB2.

Cisco IOS XE Release 2.1

This command was integrated into Cisco IOS XE Release 2.1.

12.2SX

This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.

15.0(1)M

This command was modified. The virtual-instance-name argument was added.

12.2(33)SRE

This command was modified. The virtual-instance-name argument was added.

12.2(33)XNE

This command was modified. The virtual-instance-name argument was added.

Cisco IOS XE Release 2.5

This command was modified. The virtual-instance-name argument was added.


Usage Guidelines

Configuring the router eigrp command with the autonomous-system-number argument creates an EIGRP configuration referred to as autonomous system (AS) configuration. An EIGRP AS configuration creates an EIGRP routing instance that can be used for tagging routing information.

Configuring the router eigrp command with the virtual-instance-name argument creates an EIGRP configuration referred to as EIGRP named configuration. An EIGRP named configuration does not create an EIGRP routing instance by itself. An EIGRP named configuration is a base configuration that is required to define address-family configurations under it that are used for routing.

Examples

The following example configures EIGRP process 109:

Router(config)# router eigrp 109

The following example configures an EIGRP address-family routing process and assigns it the name "virtual-name":

Router(config)# router eigrp virtual-name

Related Commands

Command
Description

network (EIGRP)

Specifies a list of networks for the EIGRP process.