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Flexible NetFlow Configuration Guide, Cisco IOS XE Gibraltar 16.12.x

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Book Title

Flexible NetFlow Configuration Guide, Cisco IOS XE Gibraltar 16.12.x

Chapter Title

Flexible NetFlow NBAR Application Recognition Overview

Results

Updated:
October 14, 2019

Chapter: Flexible NetFlow NBAR Application Recognition Overview

Flexible NetFlow NBAR Application Recognition Overview

NBAR enables creation of different flows for each application seen between any two IP hosts by applying a flow monitor having a flow record that collects the application name as a key or a nonkey field.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Information About Flexible NetFlow NBAR Application Recognition

Flexible NetFlow NBAR Application Recognition Overview

If the predefined Flexible NetFlow records are not suitable for your traffic requirements, you can create a user-defined (custom) record using the Flexible NetFlow collect and match commands. Before you can create a customized record, you must decide the criteria that you are going to use for the key and nonkey fields.

If you want to create a customized record for detecting network attacks, you must include the appropriate key and nonkey fields in the record to ensure that the router creates the flows and captures the data that you need to analyze the attack and respond to it. Flexible NetFlow uses Network-based Application recognition (NBAR) to create different flows for each application seen between any two IP hosts by applying a flow monitor having a flow record that collects the application name as a key field.

How to Configure Flexible NetFlow NBAR Application Recognition

Creating a Flow Record

Perform this task to configure a customized flow record.

Customized flow records are used to analyze traffic data for a specific purpose. A customized flow record must have at least one match criterion for use as the key field and typically has at least one collect criterion for use as a nonkey field.

There are hundreds of possible permutations of customized flow records. This task shows the steps that are used to create one of the possible permutations. Modify the steps in this task as appropriate to create a customized flow record for your requirements.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. flow record record-name
  4. description description
  5. match {ip | ipv6 } {destination | source } address
  6. Repeat Step 5 as required to configure additional key fields for the record.
  7. match flow cts {source | destination } group-tag
  8. collect interface {input | output }
  9. Repeat the above step as required to configure additional nonkey fields for the record.
  10. end
  11. show flow record record-name
  12. show running-config flow record record-name

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

flow record record-name

Example:


Device(config)# flow record FLOW-RECORD-1

Creates a flow record and enters Flexible NetFlow flow record configuration mode.

  • This command also allows you to modify an existing flow record.

Step 4

description description

Example:


Device(config-flow-record)# description Used for basic traffic analysis

(Optional) Creates a description for the flow record.

Step 5

match {ip | ipv6 } {destination | source } address

Example:


Device(config-flow-record)# match ipv4 destination address
Note 

This example configures the IPv4 destination address as a key field for the record. For information about the other key fields available for the match ipv4 command, and the other match commands that are available to configure key fields.

Step 6

Repeat Step 5 as required to configure additional key fields for the record.

—

Step 7

match flow cts {source | destination } group-tag

Example:


Device(config-flow-record)# match flow cts source group-tag

Device(config-flow-record)# match flow cts destination group-tag
Note 

This example configures the CTS source group tag and destination group tag as a key field for the record. For information about the other key fields available for the match ipv4/ ipv6 command, and the other match commands that are available to configure key fields.

Note 
  • Ingress:

    • In an incoming packet, if a header is present, SGT will reflect the same value as the header. If no value is present, it will show zero.

    • The DGT value will not depend on the ingress port SGACL configuration.

  • Egress:

    • If either propagate SGT or CTS is disabled on the egress interface, then SGT will be zero.

    • In an outgoing packet, if SGACL configuration that corresponds to the (SGT, DGT) exists, DGT will be non-zero.

    • If SGACL is disabled on the egress port/VLAN or if global SGACL enforcement is disabled, then DGT will be zero

Step 8

collect interface {input | output }

Example:


Device(config-flow-record)# collect interface input

Configures the input interface as a nonkey field for the record.

Note 

This example configures the input interface as a nonkey field for the record.

Step 9

Repeat the above step as required to configure additional nonkey fields for the record.

—

Step 10

end

Example:


Device(config-flow-record)# end

Exits Flexible NetFlow flow record configuration mode and returns to privileged EXEC mode.

Step 11

show flow record record-name

Example:


Device# show flow record FLOW_RECORD-1

(Optional) Displays the current status of the specified flow record.

Step 12

show running-config flow record record-name

Example:


Device# show running-config flow record FLOW_RECORD-1

(Optional) Displays the configuration of the specified flow record.

Creating a Flow Monitor

Perform this required task to create a customized flow monitor.

Each flow monitor has a separate cache assigned to it. Each flow monitor requires a record to define the contents and layout of its cache entries. These record formats can be a user-defined format. An advanced user can create a customized format using the flow record command.

Before you begin

If you want to use a customized record, you must create the customized record before you can perform this task. If you want to add a flow exporter to the flow monitor for data export, you must create the exporter before you can complete this task.


Note

You must use the no ip flow monitor command to remove a flow monitor from all of the interfaces to which you have applied it before you can modify the parameters for the record command on the flow monitor.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. flow monitor monitor-name
  4. description description
  5. record {record-name }
  6. cache {timeout {active } seconds | type { normal }
  7. Repeat Step 6 as required to finish modifying the cache parameters for this flow monitor.
  8. exporter exporter-name
  9. end
  10. show flow monitor [[name ] monitor-name [cache [format {csv | record | table } ]] ]
  11. show running-config flow monitor monitor-name

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


# configure terminal

Enters global configuration mode.

Step 3

flow monitor monitor-name

Example:


(config)# flow monitor FLOW-MONITOR-1

Creates a flow monitor and enters Flexible NetFlow flow monitor configuration mode.

  • This command also allows you to modify an existing flow monitor.

Step 4

description description

Example:


(config-flow-monitor)# description Used for basic ipv4 traffic analysis

(Optional) Creates a description for the flow monitor.

Step 5

record {record-name }

Example:


(config-flow-monitor)# record FLOW-RECORD-1

Specifies the record for the flow monitor.

Step 6

cache {timeout {active } seconds | type { normal }

Example:
  • type normal —Configure normal flow removal from the flow cache.
Step 7

Repeat Step 6 as required to finish modifying the cache parameters for this flow monitor.

—

Step 8

exporter exporter-name

Example:


(config-flow-monitor)# exporter EXPORTER-1

(Optional) Specifies the name of an exporter that was created previously.

Step 9

end

Example:


(config-flow-monitor)# end

Exits Flexible NetFlow flow monitor configuration mode and returns to privileged EXEC mode.

Step 10

show flow monitor [[name ] monitor-name [cache [format {csv | record | table } ]] ]

Example:


# show flow monitor FLOW-MONITOR-2 cache

(Optional) Displays the status for a Flexible NetFlow flow monitor.

Step 11

show running-config flow monitor monitor-name

Example:


# show running-config flow monitor FLOW_MONITOR-1

(Optional) Displays the configuration of the specified flow monitor.

Applying a Flow Monitor to an Interface

Before it can be activated, a flow monitor must be applied to at least one interface. Perform this required task to activate a flow monitor.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. interface type number
  4. {ip | ipv6 } flow monitor monitor-name {input | output }
  5. Repeat Steps 3 and 4 to activate a flow monitor on any other interfaces in the device over which you want to monitor traffic.
  6. end
  7. show flow interface type number
  8. show flow monitor name monitor-name cache format record

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Device# configure terminal

Enters global configuration mode.

Step 3

interface type number

Example:


Device(config)# interface GigabitEthernet 0/0/0

Specifies an interface and enters interface configuration mode.

Step 4

{ip | ipv6 } flow monitor monitor-name {input | output }

Example:


Device(config-if)# ip flow monitor FLOW-MONITOR-1 input

Activates a flow monitor that was created previously by assigning it to the interface to analyze traffic.

Step 5

Repeat Steps 3 and 4 to activate a flow monitor on any other interfaces in the device over which you want to monitor traffic.

—

Step 6

end

Example:


Device(config-if)# end

Exits interface configuration mode and returns to privileged EXEC mode.

Step 7

show flow interface type number

Example:


Device# show flow interface GigabitEthernet 0/0/0

Displays the status of Flexible NetFlow (enabled or disabled) on the specified interface.

Step 8

show flow monitor name monitor-name cache format record

Example:


Device# show flow monitor name FLOW_MONITOR-1 cache format record

Displays the status, statistics, and flow data in the cache for the specified flow monitor.

Configuration Examples for Flexible NetFlow NBAR Application Recognition

Example: Configuring Flexible NetFlow for Network-Based Application Recognition


!
flow record rm_1
match application name
match ipv4 source address
match ipv4 destination address
collect interface input
collect interface output
collect counter packets
!
flow monitor mm_1
record rm_1
!
interface FastEthernet0/0
ip address 172.16.2.2 255.255.255.0
ip flow monitor mm_1 input
!
end

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Flexible NetFlow conceptual information and configuration tasks

Flexible NetFlow Configuration Guide

Flexible NetFlow commands

Cisco IOS Flexible NetFlow Command Reference

Standards/RFCs

Standard

Title

No new or modified standards/RFCs are supported by this feature.

—

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Flexible NetFlow NBAR Application Recognition

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for Flexible NetFlow NBAR Application Recognition

Feature Name

Releases

Feature Information

Flexible NetFlow--NBAR Application Recognition

Network-based Application recognition (NBAR) enables creation of different flows for each application seen between any two IP hosts by applying a flow monitor having a flow record that collects the application name as a key or a nonkey field.

The following commands were introduced or modified: collect application name, match application name, option (Flexible NetFlow), show flow monitor.

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