IP Addressing: NAT Configuration Guide, Cisco IOS Release 15M&T
Integrating NAT with MPLS VPNs
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Integrating NAT with MPLS VPNs

Contents

Integrating NAT with MPLS VPNs

Network Address Translation (NAT) Integration with MPLS VPNs feature allows multiple Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs) to be configured on a single device to work together. NAT can differentiate which MPLS VPN it receives IP traffic from even if the MPLS VPNs are all using the same IP addressing scheme. This enhancement enables multiple MPLS VPN customers to share services while ensuring that each MPLS VPN is completely separate from the other.

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 Integrating NAT with MPLS VPNs

  • Before performing the tasks in this module, you should be familiar with the concepts described in the “Configuring NAT for IP Address Conservation” module.
  • All access lists required for use with the tasks in this module should be configured prior to beginning the configuration task. For information about how to configure an access list, see the IP Access List Sequence Numbering document at the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122s/122snwft/release/122s14/fsaclseq.htm


Note


If you specify an access list to use with a NAT command, NAT does not support the commonly used permit ip any any command in the access list.


Restrictions for Integrating NAT with MPLS VPNs

Inside VPN to VPN with NAT is not supported.

Information About Integrating NAT with MPLS VPNs

Benefits of NAT Integration with MPLS VPNs

MPLS service providers would like to provide value-added services such as Internet connectivity, domain name servers (DNS), and voice over IP (VoIP) service to their customers. The providers require that their customers; IP addresses be different when reaching the services. Because MPLS VPN allows customers to use overlapped IP addresses in their networks, NAT must be implemented to make the services possible.

Implementation Options for Integrating Nat with MPLS VPNs

There are two approaches to implementing NAT in the MPLS VPN network. NAT can be implemented on the customer edge (CE) router, which is already supported by NAT, or it can be implemented on a provider edge (PE) router. The NAT Integration with MPLS VPNs feature enables the implementation of NAT on a PE router in an MPLS cloud.

Scenarios for Implementing NAT on the PE Router

NAT could be implemented on the PE router in the following scenarios:

  • Service point--Shared access can be from a generic interface or from a VPN interface.
  • NAT point--NAT can be configured on the PE router that is directly connected to the shared access gateway, or on the PE router that is not directly connected to the shared access gateway.
  • NAT interface--The shared access gateway interface most often is configured as the outside interface of NAT. The inside interface of NAT can be either the PE-CE interface of a VPN, the interface to the MPLS backbone, or both. The shared access gateway interface can also be configured as the inside interface.
  • Routing type--Common service can be Internet connectivity or a common server. For Internet connectivity, a default route should be propagated to all the VPN customers that use the service. For common server access, a static or dynamically learned route should be propagated to the VPN customers.
  • NAT configuration--NAT can have different configurations: static, dynamic, pool/interface overloading, and route-map.

The figure below shows a typical NAT integration with MPLS VPNs. The PE router connected to the internet and centralized mail service is employed to do the address translation.

Figure 1. Typical NAT Integration with MPLS VPNs

How to Integrate NAT with MPLS VPNs

Perform one or more of the following tasks depending on the type of translation you wish to configure for your network:

Configuring Inside Dynamic NAT with MPLS VPNs

Perform this task to configure your NAT PE router for dynamic translations to integrate with MPLS VPNs.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ip nat pool name start-ip end-ip netmask netmask

    4.    ip nat [inside | outside] source [list {access-list-number | access-list-name} | route-map name] [interface type number | pool pool-name] vrf vrf-name[overload]

    5.    Repeat Step 4 for each VPN being configured

    6.    ip route vrf vrf-name prefix mask interface-type interface-number next-hop-address

    7.    Repeat Step 6 for each VPN being configured.

    8.    exit

    9.    show ip nat translations vrf vrf-name


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Router> enable
     

    Enables higher privilege levels, such as privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3 ip nat pool name start-ip end-ip netmask netmask


    Example:
    Router(config)# ip nat pool inside 2.2.2.10 2.2.2.10 netmask 255.255.255.0
     

    Defines a pool of IP addresses for NAT.

     
    Step 4 ip nat [inside | outside] source [list {access-list-number | access-list-name} | route-map name] [interface type number | pool pool-name] vrf vrf-name[overload]


    Example:
    Router(config)# ip nat inside source list 1 pool mypool vrf shop overload
     

    Allows NAT to be configured on a particular VPN.

     
    Step 5 Repeat Step 4 for each VPN being configured 

    --

     
    Step 6 ip route vrf vrf-name prefix mask interface-type interface-number next-hop-address


    Example:
    Router(config)# 
    ip route vrf shop 0.0.0.0 0.0.0.0 ethernet 0 168.58.88.2
    
     

    Allows NAT to be configured on a particular VPN.

     
    Step 7 Repeat Step 6 for each VPN being configured. 

    --

     
    Step 8 exit


    Example:
    Router(config)# exit
     

    Returns to privileged EXEC mode.

     
    Step 9 show ip nat translations vrf vrf-name


    Example:
    Router# show ip nat translations vrf shop
     

    (Optional) Displays the settings used by virtual routing/forwarding (VRF) table translations.

     

    Configuring Inside Static NAT with MPLS VPNs

    Perform this task to configure your NAT PE router for static translations to integrate with MPLS VPNs.

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    ip nat inside source {static {esp local-ip interface type number | local-ip global-ip}} [extendable | mapping-id map-id| no-alias | no-payload | redundancy group-name | route-map | vrf name]

      4.    Repeat Step 3 for each VPN being configured.

      5.    ip route vrf vrf-name prefix prefix mask next-hop-address global

      6.    Repeat Step 5 for each VPN being configured.

      7.    exit

      8.    show ip nat translations vrf vrf-name


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Router> enable
       

      Enables higher privilege levels, such as privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 configure terminal


      Example:
      Router# configure terminal
       

      Enters global configuration mode.

       
      Step 3 ip nat inside source {static {esp local-ip interface type number | local-ip global-ip}} [extendable | mapping-id map-id| no-alias | no-payload | redundancy group-name | route-map | vrf name]


      Example:
      Router(config)# 
      ip nat inside source static 192.168.121.113 2.2.2.1 vrf shop 
      
       

      Enables inside static translation on the VRF.

       
      Step 4 Repeat Step 3 for each VPN being configured. 

      --

       
      Step 5 ip route vrf vrf-name prefix prefix mask next-hop-address global


      Example:
      Router(config)# 
      ip route vrf shop 0.0.0.0 0.0.0.0 168.58.88.2 global
      
       

      Allows the route to be shared by several customers.

       
      Step 6 Repeat Step 5 for each VPN being configured. 

      --

       
      Step 7 exit


      Example:
      Router(config)# exit
       

      Returns to privileged EXEC mode.

       
      Step 8 show ip nat translations vrf vrf-name


      Example:
      Router# show ip nat translations vrf shop
       

      (Optional) Displays the settings used by VRF translations.

       

      Configuring Outside Dynamic NAT with MPLS VPNs

      Perform this step to configure your NAT PE router for dynamic outside translations to integrate with MPLS VPNs.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    ip nat pool outside global-ip local-ip netmask netmask

        4.    ip nat inside source static local-ip global-ip vrf vrf-name

        5.    Repeat Step 4 for each VRF being configured.

        6.    ip nat outside source static global-ip local-ip vrf vrf-name

        7.    exit

        8.    show ip nat translations vrf vrf-name


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Router> enable
         

        Enables higher privilege levels, such as privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 configure terminal


        Example:
        Router# configure terminal
         

        Enters global configuration mode.

         
        Step 3 ip nat pool outside global-ip local-ip netmask netmask


        Example:
        Router(config)# 
        ip nat pool outside 4.4.4.1 4.4.4.254 netmask 255.255.255.00
        
         

        Allows the configured VRF to be associated with the NAT translation rule.

         
        Step 4 ip nat inside source static local-ip global-ip vrf vrf-name


        Example:
        Router(config)# 
        ip nat inside source static 192.168.121.113 2.2.2.1 vrf shop
        
         

        Allows the route to be shared by several customers.

         
        Step 5 Repeat Step 4 for each VRF being configured. 

        Allows the route to be shared by several customers.

         
        Step 6 ip nat outside source static global-ip local-ip vrf vrf-name


        Example:
        Router(config)# 
        ip nat outside source static 168.58.88.2 4.4.4.1 vrf shop
        
         

        Enables NAT translation of the outside source address.

         
        Step 7 exit


        Example:
        Router(config)# exit
         

        Returns to privileged EXEC mode.

         
        Step 8 show ip nat translations vrf vrf-name


        Example:
        Router# show ip nat translations vrf shop
         

        (Optional) Displays the settings used by VRF translations.

         

        Configuring Outside Static NAT with MPLS VPNs

        Perform this task to configure your NAT PE router for static outside translations to integrate with MPLS VPNs.

        SUMMARY STEPS

          1.    enable

          2.    configure {terminal | memory | network}

          3.    ip nat pool inside global-ip local-ip netmask netmask

          4.    Repeat Step 3 for each pool being configured.

          5.    ip nat inside source list access-list-number pool pool-name vrf vrf-name

          6.    Repeat Step 5 for each pool being configured.

          7.    ip nat outside source static global-ip local-ip vrf vrf-name

          8.    Repeat Step 7 for all VPNs being configured.

          9.    exit

          10.    show ip nat translations vrf vrf-name


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 enable


          Example:
          Router> enable
           

          Enables higher privilege levels, such as privileged EXEC mode.

          • Enter your password if prompted.
           
          Step 2 configure {terminal | memory | network}


          Example:
          Router# configure terminal
           

          Enters global configuration mode.

           
          Step 3 ip nat pool inside global-ip local-ip netmask netmask


          Example:
          Router(config)# ip nat pool inside1 2.2.1.1 2.2.1.254 netmask 255.255.255.0
           

          Allows the configured VRF to be associated with the NAT translation rule.

           
          Step 4 Repeat Step 3 for each pool being configured. 

          --

           
          Step 5 ip nat inside source list access-list-number pool pool-name vrf vrf-name


          Example:
          Router(config)# 
          ip nat inside source list 1 pool inside2 vrf shop
          
           

          Allows the route to be shared by several customers.

           
          Step 6 Repeat Step 5 for each pool being configured. 

          Defines the access list.

           
          Step 7 ip nat outside source static global-ip local-ip vrf vrf-name


          Example:
          Router(config)# 
          ip nat outside source static 168.58.88.2 4.4.4.1 vrf shop
          
           

          Allows the route to be shared by several customers.

           
          Step 8 Repeat Step 7 for all VPNs being configured. 

          --

           
          Step 9 exit


          Example:
          Router(config)# exit
           

          Returns to privileged EXEC mode.

           
          Step 10 show ip nat translations vrf vrf-name


          Example:
          Router# show ip nat translations vrf shop
           

          (Optional) Displays the settings used by VRF translations.

           

          Configuration Examples for Integrating NAT with MPLS VPNs

          Configuring Inside Dynamic NAT with MPLS VPNs Example

          The following example shows configuring inside Dynamic NAT with MPLS VPNs.

          !
          ip nat pool inside 2.2.2.10 2.2.2.10 netmask 255.255.255.0
          ip nat inside source list 1 pool inside vrf bank overload
          ip nat inside source list 1 pool inside vrf park overload
          ip nat inside source list 1 pool inside vrf shop overload
          !
          ip route vrf shop 0.0.0.0 0.0.0.0 Ethernet1/3 168.58.88.2
          ip route vrf bank 0.0.0.0 0.0.0.0 Ethernet1/3 168.58.88.2
          ip route vrf park 0.0.0.0 0.0.0.0 Ethernet1/3 168.58.88.2
          !
          access-list 1 permit 192.168.0.0 0.0.255.255

          Configuring Inside Static NAT with MPLS VPNs Example

          The following example shows configuring inside static NAT with MPLS VPNs.

          !
          ip nat inside source static 192.168.121.113 2.2.2.1 vrf shop
          ip nat inside source static 192.168.122.49 2.2.2.2 vrf shop
          ip nat inside source static 192.168.121.113 2.2.2.3 vrf bank
          ip nat inside source static 192.168.22.49 2.2.2.4 vrf bank
          ip nat inside source static 192.168.121.113 2.2.2.5 vrf park
          ip nat inside source static 192.168.22.49 2.2.2.6 vrf park
          ip nat inside source static 192.168.11.1 2.2.2.11 vrf shop
          ip nat inside source static 192.168.11.3 2.2.2.12 vrf shop
          ip nat inside source static 140.48.5.20 2.2.2.13 vrf shop
          !
          ip route 2.2.2.1 255.255.255.255 Ethernet1/0 192.168.121.113
          ip route 2.2.2.2 255.255.255.255 Ethernet1/0 192.168.121.113
          ip route 2.2.2.3 255.255.255.255 Serial2/1.1 192.168.121.113
          ip route 2.2.2.4 255.255.255.255 Serial2/1.1 192.168.121.113
          ip route 2.2.2.5 255.255.255.255 FastEthernet0/0 192.168.121.113
          ip route 2.2.2.6 255.255.255.255 FastEthernet0/0 192.168.121.113
          ip route 2.2.2.11 255.255.255.255 Ethernet1/0 192.168.121.113
          ip route 2.2.2.12 255.255.255.255 Ethernet1/0 192.168.121.113
          ip route 2.2.2.13 255.255.255.255 Ethernet1/0 192.168.121.113

          Configuring Outside Dynamic NAT with MPLS VPNs Example

          The following example shows configuring outside dynamic NAT with MPLS VPNs.

          !
          ip nat pool outside 4.4.4.1 4.4.4.254 netmask 255.255.255.0
          ip nat inside source static 192.168.121.113 2.2.2.1 vrf shop
          ip nat inside source static 192.168.122.49 2.2.2.2 vrf shop
          ip nat inside source static 192.168.121.113 2.2.2.3 vrf bank
          ip nat inside source static 192.168.22.49 2.2.2.4 vrf bank
          ip nat inside source static 192.168.121.113 2.2.2.5 vrf park
          ip nat inside source static 192.168.22.49 2.2.2.6 vrf park
          ip nat outside source list 1 pool outside
          !

          Configuring Outside Static NAT with MPLS VPNs Example

          The following example shows configuring outside static NAT with MPLS VPNs.

          !
          ip default-gateway 10.1.15.1
          ip nat pool inside1 2.2.1.1 2.2.1.254 netmask 255.255.255.0
          ip nat pool inside2 2.2.2.1 2.2.2.254 netmask 255.255.255.0
          ip nat pool inside3 2.2.3.1 2.2.3.254 netmask 255.255.255.0
          ip nat inside source list 1 pool inside2 vrf bank
          ip nat inside source list 1 pool inside3 vrf park
          ip nat inside source list 1 pool inside1 vrf shop
          ip nat outside source static 168.58.88.2 4.4.4.1 vrf bank
          ip nat outside source static 18.68.58.1 4.4.4.2 vrf park
          ip nat outside source static 168.58.88.1 4.4.4.3 vrf shop
          ip classless
          ip route 192.170.10.0 255.255.255.0 Ethernet1/0 192.168.121.113
          ip route 192.170.11.0 255.255.255.0 Serial2/1.1 192.168.121.113
          ip route 192.170.12.0 255.255.255.0 FastEthernet0/0 192.168.121.113
          ip route vrf shop 0.0.0.0 0.0.0.0 168.58.88.2 global
          ip route vrf bank 0.0.0.0 0.0.0.0 168.58.88.2 global
          ip route vrf park 0.0.0.0 0.0.0.0 168.58.88.2 global
          no ip http server
          !
          access-list 1 permit 192.168.0.0 0.0.255.255

          Where to Go Next

          • To learn about Network Address Translation and configure NAT for IP address conservation, see the “Configuring NAT for IP Address Conservation” module.
          • To verify, monitor, and maintain NAT, see the “Monitoring and Maintaining NAT” module.
          • To use NAT with application level gateways, see the “Using Application Level Gateways with NAT” module.
          • To configure NAT for high availability, see the “Configuring NAT for High Availability” module.

          Additional References for Integrating NAT with MPLS VPNs

          Related Documents

          Related Topic

          Document Title

          IOS Commands

          Cisco IOS Master Command List

          NAT commands

          Cisco IOS IP Addressing Services Command Reference

          Standards and RFCs

          Standard & RFC

          Title

          RFC 2547

          BGP/MPLS VPNs

          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 Integrating NAT with MPLS VPNs

          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 Integrating NAT with MPLS VPNs

          Feature Name

          Releases

          Feature Configuration Information

          Integrating NAT with MPLS VPNs

          12.1(13)T

          15.1(1)SY

          The Integrating NAT with MPLS VPNs feature allows multiple Multiprotocol Label Switching (MPLS) VPNs to be configured on a single device to work together.