Table Of Contents
NAT—Static Mapping Support with HSRP for High Availability
Restrictions for Configuring Static Mapping Support for HSRP
Benefits of Configuring Static Mapping Support for HSRP
Supported Standards, MIBs, and RFCs
Enabling HSRP on the Interface
Enabling Static NAT in an HSRP Environment
Verifying HSRP on the Interface
Verifying Static NAT in an HSRP Environment
NAT—Static Mapping Support with HSRP for High Availability
Feature History
12.2(4)T
This feature was introduced.
12.2(4)T2
Support for the Cisco 7500 series routers was added.
This document describes the NAT—Static Mapping Support with HSRP for High Availability feature. It includes the following sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
When an Address Resolution Protocol (ARP) query is triggered for an address that is configured with Network Address Translation (NAT) static mapping and owned by the router, NAT responds with the BIA MAC address on the interface to which the ARP is pointing. Two routers are acting as HSRP active and standby. Their NAT inside interfaces must be enabled and configured to belong to a group.
Restrictions for Configuring Static Mapping Support for HSRP
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Benefits of Configuring Static Mapping Support for HSRP
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Related Documents
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Supported Platforms
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Determining Platform Support Through Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.
To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.
Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:
http://www.cisco.com/go/fn
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
No new or modified RFCs are supported by this feature.
Configuration Tasks
See the following sections for configuration tasks for the NAT—Static Mapping Support with HSRP for High Availability feature. Each task in the list is identified as either required or optional:
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Enabling HSRP on the Interface
To enable HSRP on the interface, use the following commands in interface configuration mode:
Enabling Static NAT in an HSRP Environment
To enable static mapping support with HSRP for high availability, use the following commands in global configuration mode, as needed:
Verifying HSRP on the Interface
To verify the HSRP configuration, use the following command in privileged EXEC mode:
Verifying Static NAT in an HSRP Environment
To verify the static NAT configuration in an HSRP environment, use the following command in privileged EXEC mode:
Configuration Examples
This section provides the following configuration example:
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Enabling Static NAT in an HSRP Environment Example
The following example shows support for NAT with a static configuration in an HSRP environment. Two routers are acting as HSRP "active" and "standby," and the NAT inside interfaces are HSRP enabled and configured to belong to the group HSRP1.
Active Router Configuration
interface BVI10ip address 192.168.5.54 255.255.255.255.0no ip redirectsip nat insidestandby 10 priority 105 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet2/1!!ip default-gateway 10.0.18.126ip nat inside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 11.11.11.0 255.255.255.0 Ethernet2/1ip route 172.22.33.0 255.255.255.0 Ethernet2/1no ip http serverStandby Router Configuration
interface BVI10ip address 192.168.5.56 255.255.255.255.0no ip redirectsip nat insidestandby 10 priority 100 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet3/1!ip default-gateway 10.0.18.126ip nat inside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 10.0.32.231 255.255.255 Ethernet3/1ip route 11.11.11.0 255.255.255.0 Ethernet3/1no ip http server
Command Reference
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publication.
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ip nat inside source
To enable Network Address Translation (NAT) of the inside source address, use the ip nat inside source command in global configuration mode. To remove the static translation or remove the dynamic association to a pool, use the no form of this command.
ip nat inside source {list {access-list-number | access-list-name} pool pool-name [overload] | static local-ip global-ip redundancy group-name}
no ip nat inside source {list {access-list-number | access-list-name} pool pool-name [overload] | static local-ip global-ip redundancy group-name}
Syntax Description
Defaults
No default behavior or values
Command Modes
Global configuration
Command History
Usage Guidelines
This command has two forms: dynamic and static address translation. The form with an access list establishes dynamic translation. Packets from addresses that match the standard access list are translated using global addresses allocated from the pool named with the ip nat pool command.
Alternatively, the syntax form with the static keyword establishes a single static translation.
Examples
The following example translates between inside hosts addressed from either the 192.168.1.0 or 192.168.2.0 network to the globally unique 171.69.233.208/28 network:
ip nat pool net-208 171.69.233.208 171.69.233.223 prefix-length 28ip nat inside source list 1 pool net-208!interface ethernet 0ip address 171.69.232.182 255.255.255.240ip nat outside!interface ethernet 1ip address 192.168.1.94 255.255.255.0ip nat inside!access-list 1 permit 192.168.1.0 0.0.0.255access-list 1 permit 192.168.2.0 0.0.0.255The following example shows support for NAT with a static configuration in an HSRP environment. Two routers are acting as HSRP "active" and "standby," and the NAT inside interfaces are HSRP enabled and configured to belong to the group HSRP1.
Active Router Configuration
interface BVI10ip address 192.168.5.54 255.255.255.255.0no ip redirectsip nat insidestandby 10 priority 105 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet2/1!!ip default-gateway 10.0.18.126ip nat inside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 11.11.11.0 255.255.255.0 Ethernet2/1ip route 172.22.33.0 255.255.255.0 Ethernet2/1no ip http serverStandby Router Configuration
interface BVI10ip address 192.168.5.56 255.255.255.255.0no ip redirectsip nat insidestandby 10 priority 100 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet3/1!ip default-gateway 10.0.18.126ip nat inside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 10.0.32.231 255.255.255 Ethernet3/1ip route 11.11.11.0 255.255.255.0 Ethernet3/1no ip http server
Related Commands
ip nat outside source
To enable Network Address Translation (NAT) of the outside source address, use the ip nat outside source command in global configuration mode. To remove the static translation or remove the dynamic association to a pool, use the no form of this command.
ip nat outside source {list {access-list-number | access-list-name} pool pool-name | static global-ip local-ip redundancy group-name}
no ip nat outside source {list {access-list-number | access-list-name} pool pool-name | static global-ip local-ip redundancy group-name}
Syntax Description
Defaults
No default behavior or values
Command Modes
Global configuration
Command History
Usage Guidelines
You might have IP addresses that are not legal, officially assigned IP addresses. Perhaps you chose IP addresses that officially belong to another network. The case of an address used illegally and legally is called overlapping. You can use NAT to translate inside addresses that overlap with outside addresses. Use this feature if your IP addresses in the stub network happen to be legitimate IP addresses belonging to another network, and you need to communicate with those hosts or routers.
This command has two forms: dynamic and static address translation. The form with an access list establishes dynamic translation. Packets from addresses that match the standard access list are translated using global addresses allocated from the pool named with the ip nat pool command.
Alternatively, the syntax form with the static keyword establishes a single static translation.
Examples
The following example translates between inside hosts addressed from the 9.114.11.0 network to the globally unique 171.69.233.208/28 network. Further packets from outside hosts addressed from the 9.114.11.0 network (the true 9.114.11.0 network) are translated to appear to be from the 10.0.1.0/24 network.
ip nat pool net-208 171.69.233.208 171.69.233.223 prefix-length 28 ip nat pool net-10 10.0.1.0 10.0.1.255 prefix-length 24ip nat inside source list 1 pool net-208ip nat outside source list 1 pool net-10!interface ethernet 0ip address 171.69.232.182 255.255.255.240ip nat outside!interface ethernet 1ip address 9.114.11.39 255.255.255.0ip nat inside!access-list 1 permit 9.114.11.0 0.0.0.255The following example shows support for NAT with a static configuration in an HSRP environment. Two routers are acting as HSRP "active" and "standby," and the NAT outside interfaces are HSRP enabled and configured to belong to the group HSRP1.
Active Router Configuration
interface BVI10ip address 192.168.5.54 255.255.255.255.0no ip redirectsip nat outsidestandby 10 priority 105 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet2/1!!ip default-gateway 10.0.18.126ip nat outside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 11.11.11.0 255.255.255.0 Ethernet2/1ip route 172.22.33.0 255.255.255.0 Ethernet2/1no ip http serverStandby Router Configuration
interface BVI10ip address 192.168.5.56 255.255.255.255.0no ip redirectsip nat outsidestandby 10 priority 100 preemptstandby 10 name HSRP1standby 10 ip 192.168.5.30standby 10 track Ethernet3/1!ip default-gateway 10.0.18.126ip nat outside source static 192.168.5.33 3.3.3.5 redundancy HSRP1ip classlessip route 10.0.32.231 255.255.255 Ethernet3/1ip route 11.11.11.0 255.255.255.0 Ethernet3/1no ip http serverRelated Commands.
Guest