Integrating NAT with MPLS VPNs

Last Updated: November 29, 2012

The 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

This feature was introduced in Cisco IOS XE 2.5. For a list of restrictions, see the Cisco IOS XE 2 Release Notes .

Information About Integrating NAT with MPLS VPNs

Benefits of NAT Integration with MPLS VPNs

For MPLS service providers to provide value-added services such as Internet connectivity, domain name servers (DNS), and VoIP service to their customers, their customers' IP addresses be unique 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 can 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 or 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 is 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 want 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 Action Purpose
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 10.2.2.10 10.2.2.10 netmask 255.0.0.0

 

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.

  • For a list of restrictions, see the Cisco IOS XE 2 Release Notes .
 
Step 5
Repeat Step 4 for each VPN being configured 

Allows NAT to be configured on additional VPNs.

 
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 fastethernet 0 192.168.88.2

 

Allows the route to be shared by customers using the specified VPN.

 
Step 7
Repeat Step 6 for each VPN being configured. 

Allows the route to be shared by customers using additional specified VPNs.

 
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 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 Action Purpose
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 10.2.2.1 vrf shop

 

Enables inside static translation on the specified VRF.

  • For a list of restrictions, see the Cisco IOS XE 2 Release Notes .
 
Step 4
Repeat Step 3 for each VPN being configured. 

Enables inside static translation on additional VRFs.

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


Example:

Router(config)# ip route vrf shop prefix 0.0.0.0 0.0.0.0 192.168.88.2 global

 

Allows the route to be shared by customers using the specified VPN.

 
Step 6
Repeat Step 5 for each VPN being configured. 

Allows the route to be shared by customers using additional specified VPNs.

 
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 name 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 Action Purpose
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 global-ip local-ip netmask netmask


Example:

Router(config)# ip nat pool out_pool 10.4.4.1 10.4.4.254 netmask 255.0.0.00

 

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 10.2.2.1 vrf shop

 

Allows the route to be shared by customers using the specified VPN.

  • For a list of restrictions, see the Cisco IOS XE 2 Release Notes .
 
Step 5
Repeat Step 4 for each VRF being configured. 

Allows the route to be shared by customers using additional specified VPNs.

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


Example:

Router(config)# i p nat outside source static 192.168.88.2 10.4.4.1 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 name 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 Action Purpose
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 name global-ip local-ip netmask netmask


Example:

Router(config)# i p nat pool in_pool 10.2.1.1 10.2.1.254 netmask 255.0.0.0

 

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

 
Step 4
Repeat Step 3 for each pool being configured. 

Allows the configured VRF to be associated with additional NAT translation rules.

 
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 in_pool vrf shop

 

Allows the route to be shared by several customers.

  • For a list of restrictions, see the Cisco IOS XE 2 Release Notes .
 
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 192.168.88.2 10.4.4.1 vrf shop

 

Allows the route to be shared by customers using the specified VPN.

 
Step 8
Repeat Step 7 for all VPNs being configured. 

Allows the route to be shared by customers using additional specified VPNs.

 
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 how to configure inside Dynamic NAT with MPLS VPNs:

!
ip nat pool inside 10.2.2.10 10.2.2.10 netmask 255.0.0.0
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 fastethernet1/3 192.168.88.2
ip route vrf bank 0.0.0.0 0.0.0.0 fastethernet1/3 192.168.88.2
ip route vrf park 0.0.0.0 0.0.0.0 fastethernet1/3 192.168.88.2
!
access-list 1 permit 192.168.0.0 0.0.255.255

Configuring Inside Static NAT with MPLS VPNs Example

The following example shows how to configure inside static NAT with MPLS VPNs:

!
ip nat inside source static 192.168.121.113 10.2.2.1 vrf shop
ip nat inside source static 192.168.122.49 10.2.2.2 vrf shop
ip nat inside source static 192.168.121.113 10.2.2.3 vrf bank
ip nat inside source static 192.168.22.49 10.2.2.4 vrf bank
ip nat inside source static 192.168.121.113 10.2.2.5 vrf park
ip nat inside source static 192.168.22.49 10.2.2.6 vrf park
ip nat inside source static 192.168.11.1 10.2.2.11 vrf shop
ip nat inside source static 192.168.11.3 10.2.2.12 vrf shop
ip nat inside source static 140.48.5.20 10.2.2.13 vrf shop
!
ip route 10.2.2.1 255.255.255.255 fastethernet1/0 192.168.121.113
ip route 10.2.2.2 255.255.255.255 fastethernet1/0 192.168.121.113
ip route 10.2.2.3 255.255.255.255 Serial2/1.1 192.168.121.113
ip route 10.2.2.4 255.255.255.255 Serial2/1.1 192.168.121.113
ip route 10.2.2.5 255.255.255.255 fastethernet0/0 192.168.121.113
ip route 10.2.2.6 255.255.255.255 fastethernet0/0 192.168.121.113
ip route 10.2.2.11 255.255.255.255 fastethernet1/0 192.168.121.113
ip route 10.2.2.12 255.255.255.255 fastethernet1/0 192.168.121.113
ip route 10.2.2.13 255.255.255.255 fastethernet1/0 192.168.121.113

Configuring Outside Dynamic NAT with MPLS VPNs Example

The following example shows how to configure outside dynamic NAT with MPLS VPNs:

!
ip nat pool outside 10.4.4.1 10.4.4.254 netmask 255.0.0.0
ip nat inside source static 192.168.121.113 10.2.2.1 vrf shop
ip nat inside source static 192.168.122.49 10.2.2.2 vrf shop
ip nat inside source static 192.168.121.113 10.2.2.3 vrf bank
ip nat inside source static 192.168.22.49 10.2.2.4 vrf bank
ip nat inside source static 192.168.121.113 10.2.2.5 vrf park
ip nat inside source static 192.168.22.49 10.2.2.6 vrf park
ip nat outside source list 1 pool outside
!

Configuring Outside Static NAT with MPLS VPNs Example

The following example shows how to configure outside static NAT with MPLS VPNs:

!
ip default-gateway 10.1.15.1
ip nat pool inside1 10.2.1.1 10.2.1.254 netmask 255.0.0.0
ip nat pool inside2 10.2.2.1 10.2.2.254 netmask 255.0.0.0
ip nat pool inside3 10.2.3.1 10.2.3.254 netmask 255.0.0.0
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 192.168.88.2 10.4.4.1 vrf bank
ip nat outside source static 10.68.58.1 10.4.4.2 vrf park
ip nat outside source static 192.168.88.1 10.4.4.3 vrf shop
ip classless
ip route 172.16.10.0 255.255.255.0 fastethernet 1/0 192.168.121.113
ip route 172.16.11.0 255.255.255.0 Serial 2/1.1 192.168.121.113
ip route 172.16.12.0 255.255.255.0 fastethernet 0/0 192.168.121.113
ip route vrf shop 0.0.0.0 0.0.0.0 192.168.88.2 global
ip route vrf bank 0.0.0.0 0.0.0.0 192.168.88.2 global
ip route vrf park 0.0.0.0 0.0.0.0 192.168.88.2 global
no ip http server
!
access-list 1 permit 192.168.0.0 0.0.255.255

Where to Go Next

For more information about configuring IP applications and services, see the IP SLAs Configuration Guide Cisco IOS XE Release 3S.

Additional References

The following sections provide references related to NAT.

Related Documents

Related Topic

Document Title

NAT commands: complete command syntax, command mode, command history, defaults, usage guidelines and examples

Cisco IOS IP Addressing Services Command Reference

Configuring an access list

IP Access List Sequence Numbering

NAT high availability

"Configuring NAT for High Availability" module

Application-level gateways

"Using Application Level Gateways with NAT"

Maintain and monitor NAT

"Monitoring and Maintaining NAT" module

IP address conservation

"Configuring NAT for IP Address Conservation" module

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

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

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

RFCs

RFCs1

Title

RFC 2547

BGP/MPLS VPNs

1 Not all supported RFCs are listed.

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

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

NAT Integration with MPLS VPNs feature

Cisco IOS XE Release 2.5

This feature allows multiple Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs) to be configured on a single device to work together.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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