Multitopology Routing Configuration Guide, Cisco IOS XE Release 3S
Knob for Ping and Traceroute with VRF to Choose Global DNS Server
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Knob for Ping and Traceroute with VRF to Choose Global DNS Server

Contents

Knob for Ping and Traceroute with VRF to Choose Global DNS Server

This feature provides a knob for ping and trace route with VRF to choose global DNS server when no DNS servers are defined in a VRF. This module explains how to configure Knob for Ping and Traceroute with VRF to choose Global DNS Server.

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 at the end of this module.

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.

Prerequisites for Knob for Ping and Traceroute with VRF to Choose Global DNS Server

  • VRF must be configured.

Information About Knob for Ping and Traceroute with VRF to Choose Global DNS Server

Overview of Knob for Ping and Traceroute with VRF to Choose Global DNS Server

Prior to the Knob for Ping and Traceroute with VRF to choose Global DNS Server feature, ping or traceroute in VRF would look up only in the specified name server to resolve the domain name. If DNS server is specified in the VRF, the DNS is used to resolve the domain name. If DNS server is not specified in the VRF, the DNS fails to resolve the domain name.

With the implementation of the Knob for Ping and Traceroute with VRF to choose Global DNS Server feature, ping and traceroute uses VRF DNS server (if the server is already configured in a VRF), otherwise global DNS server is used to resolve the domain name. The ip global-nameserver command acts as a knob that facilitates the ping and traceroute to use the VRF DNS server or the global DNS server when the server is not configured in a VRF.

How to Configure Knob for Ping and Traceroute with VRF to Choose Global DNS Server

Configuring a Knob for Ping and Traceroute with VRF to Choose Global DNS Server

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ip global-nameserver

    4.    exit


DETAILED STEPS
     Command or ActionPurpose
    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 ip global-nameserver


    Example:
    Device(config)# ip global-nameserver
     

    Configures a knob for ping and traceroute to use VRF DNS server for resolving the domain name.

     
    Step 4 exit


    Example:
    Device(config)# exit
     

    Exits global configuration mode.

     

    Configuration Examples for Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    Example: Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    Device> enable
    Device# configure terminal
    Device(config)# ip global-nameserver
    Device(config)# exit
    

    Additional References for Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    Related Documents

    Related Topic

    Document Title

    Cisco IOS commands

    Cisco IOS Master Command List, All Releases

    Multitopology Routing (MTR) commands

    Cisco IOS Multitopology Routing Command Reference

    MTR in VRF

    Multitopology Routing Configuration Guide

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    Feature Information for Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    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 Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    Feature Name

    Releases

    Feature Information

    Knob for Ping and Traceroute with VRF to Choose Global DNS Server

    Cisco IOS XE Release 3.12S

    This feature provides a knob for ping and trace route with VRF to choose global DNS server when no DNS servers are defined in a VRF.

    The following commands were introduced or modified: ip global-nameserver.