NetFlow - Configuring NDE [Support]

Table Of Contents

Configuring NDE

Understanding NDE

NDE Overview

NDE on the RP

NDE on the PFC

NDE Flow Mask

Additional NDE Fields

NDE Versions

Exporting NetFlow Data

Sampled NetFlow

Default NDE Configuration

NDE Configuration Guidelines and Restrictions

Configuring NDE

Configuring NDE on the PFC

Enabling NDE From the PFC

Populating Additional NDE Fields

Configuring Sampled NetFlow

Configuring NDE on the RP

Configuring the RP NDE Source Layer 3 Interface

Configuring the NDE Destination

Configuring Sampled NetFlow

Enabling NDE for Ingress-Bridged IP Traffic

Displaying the NDE Address and Port Configuration

Configuring NDE Flow Filters

NDE Flow Filter Overview

Configuring a Port Flow Filter

Configuring a Host and Port Filter

Configuring a Host Flow Filter

Configuring a Protocol Flow Filter

Displaying the NDE Configuration

Configuring NDE

This chapter describes how to configure NetFlow Data Export (NDE).

Note For complete syntax and usage information for the commands used in this chapter, see these publications:

•The Cisco IOS Software Releases 12.2SX Command References at this URL:

http://www.cisco.com/en/US/docs/ios/mcl/122sx_mcl.html

•The Release 12.2 publications at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/index.htm

•NetFlow version 9 is described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123_1/nfv9expf.htm

This chapter contains the following sections:

•Understanding NDE

•Default NDE Configuration

•NDE Configuration Guidelines and Restrictions

•Configuring NDE

Understanding NDE

These sections describe how NetFlow Data Export (NDE) works:

•NDE Overview

•NDE on the RP

NDE Overview

NetFlow collects traffic statistics by monitoring the packets that flow through the switch and storing the statistics in the NetFlow table. For more information about NetFlow, see Chapter 55, "Configuring NetFlow."

NetFlow Data Export (NDE) converts the NetFlow table statistics into records and exports the records to an external device, which is called a NetFlow collector.

In PFC3A mode, NDE exports statistics only for routed traffic. With modes other than PFC3A, you can configure NDE to export statistics for both routed and bridged traffic.

You can export IP unicast statistics using NDE record format versions 5, 7 or 9. Use NDE version 8 record format for NetFlow aggregation, and version 9 record format for IP multicast.

Exporting a large volume of statistics can significantly impact SP and RP CPU utilization. You can control the volume of records exported by configuring NDE flow filters to include or exclude flows from the NDE export. When you configure a filter, NDE exports only the flows that match the filter criteria.

You can configure up to two external data collector addresses. A second data collector improves the probability of receiving complete NetFlow data by providing redundant data streams.

NDE on the RP

NDE on the route processor (RP) exports statistics for flows routed in software. The RP supports NetFlow aggregation, described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fswtch_c/swprt2/xcfnfov.htm#wp1001212

The RP also supports NetFlow ToS-based router aggregation, described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s15/dtnfltos.htm

Sampled NetFlow on the RP is described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122sb/cr/sbnf_r/nf_c1sb.htm#wp1026620

NetFlow version 9 is described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123_1/nfv9expf.htm

NetFlow version 9 record formats are described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/honf_c/chap05/onf_bcf.htm#wp1180857

NDE on the PFC

NDE on the PFC exports statistics for flows routed or bridged in hardware. These sections describe NDE on the PFC in more detail:

•NDE Flow Mask

•NDE Versions

•Exporting NetFlow Data

•Sampled NetFlow

NDE Flow Mask

You can configure the minimum NetFlow flow mask for NDE. The NetFlow flow mask determines the granularity of the statistics gathered, which controls the volume of statistics for NDE to export.

For more details about flow masks, see Chapter 55, "Configuring NetFlow."

Additional NDE Fields

You can configure NDE to populate the following additional fields in the NDE packets:

•IP address of the next hop router

•Egress interface SNMP ifIndex

•BGP AS

These fields are populated by the software looking up the FIB table entry before sending out the NDE record to the collector. Therefore, these fields are blank when you use the show command to display the hardware NetFlow table.

NDE Versions

NetFlow version 9 is described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123_1/nfv9expf.htm

NDE exports statistics for NetFlow aggregation flows using NDE version 8. The following document describes the version 8 header format:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fswtch_c/swprt2/xcfnfov.htm#wp1001212

NDE exports IP unicast traffic using NDE versions 5, 7 and 9.

Some fields in the flow records might not have values, depending on the current flow mask. Unsupported fields contain a zero (0).

The following tables describe the supported fields for NDE versions 5 and 7:

•Table 56-1—Version 5 header format

•Table 56-2—Version 7 header format

•Table 56-3—Version 5 flow record format

•Table 56-4—Version 7 flow record format

NetFlow version 9 record formats are described at this URL:

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a00805e395a.html#wp1180857

Table 56-1 NDE Version 5 Header Format

Bytes

Content

Description

0-1

version

NetFlow export format version number

2-3

count

Number of flows exported in this packet (1-30)

4-7

SysUptime

Current time in milliseconds since router booted

8-11

unix_secs

Current seconds since 0000 UTC 1970

12-15

unix_nsecs

Residual nanoseconds since 0000 UTC 1970

16-19

flow_sequence

Sequence counter of total flows seen

20-21

engine_type

Type of flow switching engine

21-23

engine_id

Slot number of the flow switching engine

Table 56-2 NDE Version 7 Header Format

Bytes

Content

Description

0-1

version

NetFlow export format version number

2-3

count

Number of flows exported in this packet (1-30)

4-7

SysUptime

Current time in milliseconds since router booted

8-11

unix_secs

Current seconds since 0000 UTC 1970

12-15

unix_nsecs

Residual nanoseconds since 0000 UTC 1970

16-19

flow_sequence

Sequence counter of total flows seen

20-23

reserved

Unused (zero) bytes

Table 56-3 NDE Version 5 Flow Record Format

Bytes

Content

Description

Flow masks:

· X=Populated

· A=Additional field (see the "Populating Additional NDE Fields" section)

Source

Destination

Destination
Source

Destination
Source
Interface

Full

Full
Interface

0-3

srcaddr

Source IP address

X

0

X

X

X

X

4-7

dstaddr

Destination IP address

0

X

X

X

X

X

8-11

nexthop

Next hop router's IP address¹

0

A²

A

A

A

A

12-13

input

Ingress interface SNMP ifIndex

0

0

0

X

0

X

14-15

output

Egress interface SNMP ifIndex³

0

A2

A

A

A

A

16-19

dPkts

Packets in the flow

X

X

X

X

X

X

20-23

dOctets

Octets (bytes) in the flow

X

X

X

X

X

X

24-27

first

SysUptime at start of the flow (milliseconds)

X

X

X

X

X

X

28-31

last

SysUptime at the time the last packet of the flow was received (milliseconds)

X

X

X

X

X

X

32-33

srcport

Layer 4 source port number or equivalent

0

0

0

0

X⁴

X4

34-35

dstport

Layer 4 destination port number or equivalent

0

0

0

0

X

X

36

pad1

Unused (zero) byte

0

0

0

0

0

0

37

tcp_flags

Cumulative OR of TCP flags⁵

0

0

0

0

0

0

38

prot

Layer 4 protocol (for example, 6=TCP, 17=UDP)

0

0

0

0

X

X

39

tos

IP type-of-service byte

X⁶

X6

X6

X6

X6

X6

40-41

src_as

Autonomous system number of the source, either origin or peer

X

0

X

X

X

X

42-43

dst_as

Autonomous system number of the destination, either origin or peer

0

X

X

X

X

X

44-45

src_mask

Source address prefix mask bits

X

0

X

X

X

X

46-47

dst_mask

Destination address prefix mask bits

0

X

X

X

X

X

48

pad2

Pad 2

0

0

0

0

0

0

¹Always zero when PBR, WCCP, or SLB is configured.

²With the destination flow mask, the "Next hop router's IP address" field and the "Output interface's SNMP ifIndex" field might not contain information that is accurate for all flows.

³Always zero when policy-based routing is configured.

⁴Except in PFC3A mode, for ICMP traffic, contains the ICMP code and type values.

⁵Always zero for hardware-switched flows.

⁶Not populated in PFC3A mode.

Table 56-4 NDE Version 7 Flow Record Format

Bytes

Content

Description

Flow masks:

· X=Populated

· A=Additional field (see the "Populating Additional NDE Fields" section)

Source

Destination

Destination
Source

Destination
Source
Interface

Full

Full
Interface

0-3

srcaddr

Source IP address

X

0

X

X

X

X

4-7

dstaddr

Destination IP address

0

X

X

X

X

X

8-11

nexthop

Next hop router's IP address¹

0

A²

A

A

A

A

12-13

input

Ingress interface SNMP ifIndex

0

0

0

X

0

X

14-15

output

Egress interface SNMP ifIndex³

0

A2

A

A

A

A

16-19

dPkts

Packets in the flow

X

X

X

X

X

X

20-23

dOctets

Octets (bytes) in the flow

X

X

X

X

X

X

24-27

First

SysUptime at start of the flow (milliseconds)

X

X

X

X

X

X

28-31

Last

SysUptime at the time the last packet of the flow was received (milliseconds)

X

X

X

X

X

X

32-33

srcport

Layer 4 source port number or equivalent

0

0

0

0

X⁴

X4

34-35

dstport

Layer 4 destination port number or equivalent

0

0

0

0

X

X

36

flags

Flow mask in use

X

X

X

X

X

X

37

tcp_flags

Cumulative OR of TCP flags⁵

0

0

0

0

0

0

38

prot

Layer 4 protocol (for example, 6=TCP, 17=UDP)

0

0

0

0

X

X

39

tos

IP type-of-service byte

X⁶

X6

X6

X6

X6

X6

40-41

src_as

Autonomous system number of the source, either origin or peer

X

0

X

X

X

X

42-43

dst_as

Autonomous system number of the destination, either origin or peer

0

X

X

X

X

X

44

src_mask

Source address prefix mask bits

X

0

X

X

X

X

45

dst_mask

Destination address prefix mask bits

0

X

X

X

X

X

46-47

pad2

Pad 2

0

0

0

0

0

0

48-51

MLS RP

IP address of MLS router

0

X

X

X

X

X

¹Always zero when PBR, WCCP, or SLB is configured.

²With the destination flow mask, the "Next hop router's IP address" field and the "Output interface's SNMP ifIndex" field might not contain information that is accurate for all flows.

³Always zero when policy-based routing is configured.

⁴Except in PFC3A mode, for ICMP traffic, contains the ICMP code and type values.

⁵Always zero for hardware-switched flows.

⁶Not populated in PFC3A mode.

Exporting NetFlow Data

NetFlow maintains traffic statistics for each active flow in the NetFlow table and increments the statistics when packets within each flow are switched.

Periodically, NDE exports summarized traffic statistics for all expired flows, which the external data collector receives and processes.

Exported NetFlow data contains statistics for the flow entries in the NetFlow table that have expired since the last export. Flow entries in the NetFlow table expire and are flushed from the NetFlow table when one of the following conditions occurs:

•The entry ages out.

•The entry is cleared by the user.

•An interface goes down.

•Route flaps occur.

To ensure periodic reporting of continuously active flows, entries for continuously active flows expire at the end of the interval configured with the mls aging long command (default 32 minutes).

NDE packets go to the external data collector either when the number of recently expired flows reaches a predetermined maximum or after 30 seconds.

By default, all expired flows are exported unless they are filtered. If you configure a filter, NDE only exports expired and purged flows that match the filter criteria. NDE flow filters are stored in NVRAM and are not cleared when NDE is disabled. See the "Configuring NDE Flow Filters" section for NDE filter configuration procedures.

Sampled NetFlow

Use the Sampled NetFlow feature to export data for a subset of traffic in a flow instead of for all packets in the flow. Sampled NetFlow can substantially reduce the amount of data to be exported.

Sampled NetFlow always uses the interface-full flow mask.

If you are using either the interface-full or interface-destination-source flow masks, you can enable or disable sampled NetFlow on each Layer 3 interface. You can enable sampled NetFlow on a Layer 2 interface if you have enabled NetFlow for bridged traffic on that interface. For further details, see the "Enabling NetFlow for Ingress-Bridged IP Traffic" section on page 55-11.

You can configure sampled NetFlow to use time-based sampling or packet-based sampling.

Table 56-5 lists the time-based sampling rates and export intervals.

Table 56-5 Time-Based Sampling Rates, Sampling Times, and Export Intervals

Sampling Rate

Sampling Time (Milliseconds)

Export Interval (Milliseconds)

1 in 64

128

8192

1 in 128

64

8192

1 in 256

32

8192

1 in 512

16

8192

1 in 1024

8

8192

1 in 2048

4

8192

1 in 4096

4

16384

1 in 8192

4

32768

If you configure 64 as the rate, the sampled NefFlow feature uses traffic from the first 64 milliseconds of a flow every 8192 milliseconds. If the rate is 2048, the sampled NetFlow feature uses traffic from the first 4 milliseconds of a flow every 8192 milliseconds. With time-based sampled NetFlow, the export interval is not configurable.

Packet-based sampled NetFlow uses this formula to sample a flow: the number of times sampled is approximately the length divided by the rate (packets_in_flow/sampling_rate). For example, if the flow is 32,768 packets long and the sampling rate is 1024, the flow is sampled approximately 32 times (32,768/1,024). With packet-based sampled NetFlow, the export interval is configurable.

Default NDE Configuration

Table 56-6 shows the default NDE configuration.

Table 56-6 Default NDE Configuration

Feature

Default Value

NDE

Disabled

NDE of ingress bridged IP traffic

Disabled

NDE source addresses

None

NDE data collector address and UDP port

None

NDE filters

None

Populating additional NDE fields

Enabled

NDE Configuration Guidelines and Restrictions

When configuring NDE, follow these guidelines and restrictions:

•You must enable NetFlow on the PFC to export data for packets forwarded in hardware.

•When you configure NAT and NDE on an interface, the PFC sends all fragmented packets to the RP to be processed in software. (CSCdz51590)

•NDE supports IP multicast traffic only with NetFlow version 9.

•NetFlow aggregation must use NDE version 8 or version 9.

•Except in PFC3A mode, NDE supports bridged IP traffic. PFC3A mode does not support NDE for bridged IP traffic.

•NDE does not support Internetwork Packet Exchange (IPX) traffic or any other non-IP protocol.

Configuring NDE

These sections describe how to configure NDE:

•Configuring NDE on the PFC

•Configuring NDE on the RP

•Enabling NDE for Ingress-Bridged IP Traffic

•Displaying the NDE Address and Port Configuration

•Configuring NDE Flow Filters

•Displaying the NDE Configuration

Configuring NDE on the PFC

These sections describe how to configure NDE on the PFC:

•Enabling NDE From the PFC

•Populating Additional NDE Fields

•Configuring Sampled NetFlow

Enabling NDE From the PFC

To enable NDE from the PFC, perform this task:

Command

Purpose

Router(config)# mls nde sender [version {5 | 7}]

Enables NDE from the PFC and (optionally) configures the NDE version.

Do not use this command to enable version 9 records. Instead, use ip flow-export version 9, which is explained in the "Configuring NDE on the RP" section.

Router(config)# no mls nde sender

Disables NDE from the PFC.

Router(config)# no mls nde sender version

Reverts to the default (version 7).

Note•NDE from the PFC uses the source interface configured for the RP (see the "Configuring the RP NDE Source Layer 3 Interface" section).

•NetFlow version 9 is described at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123_1/nfv9expf.htm

This example shows how to enable NDE from the PFC:
Router(config)# mls nde sender 
This example shows how to enable NDE from the PFC and configure NDE version 5:
Router(config)# mls nde sender version 5 
Populating Additional NDE Fields

You can configure NDE to populate the following additional fields in the NDE packets:

•IP address of the next hop router

•Egress interface SNMP ifIndex

•BGP AS

Not all of the additional fields are populated with all flow masks. See the "NDE Versions" section for additional information.

To populate the additional fields in NDE packets, perform this task:

Command

Purpose

Router(config)# mls nde interface

Populates additional fields in NDE packets.

Router(config)# no mls nde interface

Disables population of the additional fields.

This example shows how to populate the additional fields in NDE packets:
Router(config)# mls nde interface 
Configuring Sampled NetFlow

These sections describe how to configure sampled NetFlow on the PFC:

•Configuring Sampled NetFlow Globally

•Configuring Sampled NetFlow on a Layer 3 Interface

Configuring Sampled NetFlow Globally

To configure sampled NetFlow globally, perform this task:

Command

Purpose

Step 1

Router(config)# mls sampling {time-based rate | packet-based rate [interval]}

Enables sampled NetFlow and configures the rate. For packet-based sampling, optionally configures the export interval.

Router(config)# no mls sampling

Clears the sampled NetFlow configuration.

Step 2

Router(config)# end

Exits configuration mode.

When you configure sampled NetFlow globally, note the following information:

•The valid values for rate are 64, 128, 256, 512, 1024, 2048, 4096, and 8192.

•The valid values for the packet-based export interval are from 8,000 through 16,000.

•To export any data, you must also configure sampled NetFlow on a Layer 3 interface.

Configuring Sampled NetFlow on a Layer 3 Interface

Note•With the full-interface or destination-source-interface flow masks, you can enable or disable sampled NetFlow on individual Layer 3 interfaces. With all other flow masks, sampled NetFlow is enabled or disabled globally.

•The Layer 3 interface must be configured with an IP address.

To configure sampled NetFlow on a Layer 3 interface, perform this task:

Command

Purpose

Step 1

Router(config)# interface {vlan vlan_ID | type slot/port}

Selects a Layer 3 interface to configure.

Step 2

Router(config-if)# mls netflow sampling

Enables sampled NetFlow on the Layer 3 interface.

Router(config-if)# no mls netflow sampling

Disables sampled NetFlow on the Layer 3 interface.

Step 3

Router(config)# end

Exits configuration mode.

This example shows how to enable sampled NetFlow on Fast Ethernet port 5/12:
Router# configure terminal 
Router(config)# interface fastethernet 5/12 
Router(config-if)# mls netflow sampling 
Router(config)# end 
Router#
Configuring NDE on the RP

These sections describe how to configure NDE on the RP:

•Configuring the RP NDE Source Layer 3 Interface

•Configuring the NDE Destination

•Configuring Sampled NetFlow

Configuring the RP NDE Source Layer 3 Interface

To configure the Layer 3 interface used as the source of the NDE packets containing statistics from the RP, perform this task:

Command

Purpose

Router(config)# ip flow-export source {{vlan vlan_ID} | {type slot/port} | {port-channel number} | {loopback number}}

Configures the interface used as the source of the NDE packets containing statistics from the RP.

Router(config)# no ip flow-export source

Clears the NDE source interface configuration.

When configuring the RP NDE source Layer 3 interface, note the following information:

•You must select an interface configured with an IP address.

•You can use a loopback interface.

This example shows how to configure a loopback interface as the NDE flow source:
Router(config)# ip flow-export source loopback 0 
Router(config)#
Configuring the NDE Destination

To configure the destination IP address and UDP port to receive the NDE statistics, perform this task:

Command

Purpose

Router(config)# ip flow-export destination ip_address udp_port_number [vrf vrf_name]

Configures the NDE destination IP address and UDP port.

(Optional) Specify a VPN routing/forwarding table name.

Router(config)# no ip flow-export destination ip_address udp_port_number [vrf vrf_name]

Clears the NDE destination configuration.

Note NetFlow Multiple Export Destinations—To configure redundant NDE data streams, which improves the probability of receiving complete NetFlow data, you can enter the ip flow-export destination command twice and configure a different destination IP address in each command. Configuring two destinations increases the RP CPU utilization, as you are exporting the data records twice.

This example shows how to configure the NDE flow destination IP address and UDP port:
Router(config)# ip flow-export destination 172.20.52.37 200 
Note The destination address and UDP port number are saved in NVRAM and are preserved if NDE is disabled and reenabled or if the switch is power cycled. If you are using the NetFlow FlowCollector application for data collection, verify that the UDP port number you configure is the same port number shown in the FlowCollector's /opt/csconfc/config/nfconfig.file file.

Configuring Sampled NetFlow

The RP supports sampled NetFlow for software-routed traffic.

For additional information, see the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122sb/cr/sbnf_r/nf_c1sb.htm#wp1026620

Enabling NDE for Ingress-Bridged IP Traffic

Except in PFC3A mode, NDE supports ingress-bridged IP traffic. PFC3A mode does not support NDE for bridged IP traffic.

NDE is enabled by default when you enable NetFlow on the VLAN. For additional information, see "Configuring NetFlow on Layer 3 Interfaces" section on page 55-11.

To disable NDE for ingress-bridged IP traffic in VLANs, perform this task:

Command

Purpose

Router(config)# ip flow export layer2-switched vlan vlan_ID[-vlan_ID] [, vlan_ID[-vlan_ID]]

Enables NDE for ingress-bridged IP traffic in the specified VLANs (enabled by default when you enter the ip flow ingress layer2-switched vlan command).

Note NDE for ingress-bridged IP traffic in a VLAN requires that NDE on the PFC be enabled with the mls nde sender command.

Router(config)# no ip flow export layer2-switched vlan vlan_ID[-vlan_ID] [, vlan_ID[-vlan_ID]]

Disables NDE for ingress-bridged IP traffic in the specified VLANs.

This example shows how to enable NDE for ingress bridged IP traffic in VLAN 200:
Router# configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# ip flow export layer2-switched vlan 200 
Displaying the NDE Address and Port Configuration

To display the NDE address and port configuration, perform these tasks:

Command

Purpose

Router# show mls nde

Displays NDE information for hardware flows including the NDE export flow IP address, UDP port, and the NDE source interface configuration.

Router# show ip flow export

Displays NDE information for software flows including the NDE export flow IP address, UDP port, and the NDE source interface configuration.

This example shows how to display the NDE export flow source IP address and UDP port configuration:
Router# show mls nde 
Netflow Data Export enabled
 Exporting flows to  10.34.12.245 (9999)
 Exporting flows from 10.6.58.7 (55425)
 Version: 7
 Include Filter not configured
 Exclude Filter is:
   source:  ip address 11.1.1.0, mask 255.255.255.0
 Total Netflow Data Export Packets are:
    49 packets, 0 no packets, 247 records
 Total Netflow Data Export Send Errors:
        IPWRITE_NO_FIB = 0
        IPWRITE_ADJ_FAILED = 0
        IPWRITE_PROCESS = 0
        IPWRITE_ENQUEUE_FAILED = 0
        IPWRITE_IPC_FAILED = 0
        IPWRITE_OUTPUT_FAILED = 0
        IPWRITE_MTU_FAILED = 0
        IPWRITE_ENCAPFIX_FAILED = 0
 Netflow Aggregation Enabled
   source-prefix aggregation export is disabled
   destination-prefix aggregation exporting flows to 10.34.12.245 (9999)
10.34.12.246 (9909)
      exported 84 packets, 94 records
   prefix aggregation export is disabled
Router# 
This example shows how to display the NDE export flow IP address, UDP port, and the NDE source interface configuration:
Router# show ip flow export 
Flow export is enabled
  Exporting flows to 172.20.52.37 (200)
  Exporting using source interface FastEthernet5/8
  Version 1 flow records
  0 flows exported in 0 udp datagrams
  0 flows failed due to lack of export packet
  0 export packets were sent up to process level
  0 export packets were dropped due to no fib
  0 export packets were dropped due to adjacency issues
Router# 
Configuring NDE Flow Filters

These sections describe NDE flow filters:

•NDE Flow Filter Overview

•Configuring a Port Flow Filter

•Configuring a Host and Port Filter

•Configuring a Host Flow Filter

•Configuring a Protocol Flow Filter

NDE Flow Filter Overview

By default, all expired flows are exported until you configure a filter. After you configure a filter, only expired and purged flows matching the specified filter criteria are exported. Filter values are stored in NVRAM and are not cleared when NDE is disabled.

To display the configuration of the NDE flow filters you configure, use the show mls nde command described in the "Displaying the NDE Configuration" section.

Configuring a Port Flow Filter

To configure a destination or source port flow filter, perform this task:

Command

Purpose

Router(config)# mls nde flow {exclude | include} {dest-port number | src-port number}

Configures a port flow filter for an NDE flow.

Router(config)# no mls nde flow {exclude | include}

Clears the port flow filter configuration.

This example shows how to configure a port flow filter so that only expired flows to destination port 23 are exported (assuming the flow mask is set to full):
Router(config)# mls nde flow include dest-port 23 
Router(config)#
Configuring a Host and Port Filter

To configure a host and TCP/UDP port flow filter, perform this task:

Command

Purpose

Router(config)# mls nde flow {exclude | include} {destination ip_address mask | source ip_address mask {dest-port number | src-port number}}

Configures a host and port flow filter for an NDE flow.

Router(config)# no mls nde flow {exclude | include}

Clears the port flow filter configuration.

This example shows how to configure a source host and destination TCP/UDP port flow filter so that only expired flows from host 171.69.194.140 to destination port 23 are exported (assuming the flow mask is set to ip-flow):
Router(config)# mls nde flow include source 171.69.194.140 255.255.255.255 dest-port 23 
Configuring a Host Flow Filter

To configure a destination or source host flow filter, perform this task:

Command

Purpose

Router(config)# mls nde flow {exclude | include} {destination ip_address mask | source ip_address mask | protocol {tcp {dest-port number | src-port number} | udp {dest-port number | src-port number}}

Configures a host flow filter for an NDE flow.

Router(config)# no mls nde flow {exclude | include}

Clears port filter configuration.

This example shows how to configure a host flow filter to export only flows to destination host 172.20.52.37:
Router(config)# mls nde flow include destination 172.20.52.37 255.255.255.225 
Router(config)# 
Configuring a Protocol Flow Filter

To configure a protocol flow filter, perform this task:

Command

Purpose

Router(config)# mls nde flow {exclude | include} protocol {tcp {dest-port number | src-port number} | udp {dest-port number | src-port number}}

Configures a protocol flow filter for an NDE flow.

Router(config)# no mls nde flow {exclude | include}

Clears port filter configuration.

This example shows how to configure a TCP protocol flow filter so that only expired flows from destination port 35 are exported:
Router(config)# mls nde flow include protocol tcp dest-port 35 
Router(config)#
To display the status of the NDE flow filters, use the show mls nde command described in the "Displaying the NDE Configuration" section.

Displaying the NDE Configuration

To display the NDE configuration, perform this task:

Command

Purpose

Router# show mls nde

Displays the NDE configuration.

This example shows how to display the NDE configuration:
Router# show mls nde 
 Netflow Data Export enabled
 Exporting flows to  10.34.12.245 (9988)  10.34.12.245 (9999)
 Exporting flows from 10.6.58.7 (57673)
 Version: 7
 Include Filter not configured
 Exclude Filter not configured
 Total Netflow Data Export Packets are:
    508 packets, 0 no packets, 3985 records
 Total Netflow Data Export Send Errors:
        IPWRITE_NO_FIB = 0
        IPWRITE_ADJ_FAILED = 0
        IPWRITE_PROCESS = 0
        IPWRITE_ENQUEUE_FAILED = 0
        IPWRITE_IPC_FAILED = 0
        IPWRITE_OUTPUT_FAILED = 0
        IPWRITE_MTU_FAILED = 0
        IPWRITE_ENCAPFIX_FAILED = 0
 Netflow Aggregation Enabled 
Router# 