Integrating NAT with MPLS VPNs
ErrorMessage : Error while constructing the Hinav

null
Downloads: This chapterpdf (PDF - 210.0KB) | Feedback

Integrating NAT with MPLS VPNs

Table Of Contents

Integrating NAT with MPLS VPNs

Contents

Prerequisites for Integrating NAT with MPLS VPNs

Restrictions for Integrating NAT with MPLS VPNs

Information About Integrating NAT with MPLS VPNs

Benefits of NAT Integration with MPLS VPNs

Implementation Options for Integrating NAT with MPLS VPNs

Scenarios for Implementing NAT on the PE Router

How to Integrate NAT with MPLS VPNs

Configuring Inside Dynamic NAT with MPLS VPNs

Configuring Inside Static NAT with MPLS VPNs

Configuring Outside Dynamic NAT with MPLS VPNs

Configuring Outside Static NAT with MPLS VPNs

Configuration Examples for Integrating NAT with MPLS VPNs

Configuring Inside Dynamic NAT with MPLS VPNs: Example

Configuring Inside Static NAT with MPLS VPNs: Example

Configuring Outside Dynamic NAT with MPLS VPNs: Example

Configuring Outside Static NAT with MPLS VPNs: Example

Where to Go Next

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Integrating NAT with MPLS VPNs


Integrating NAT with MPLS VPNs


First Published: May 2, 2005
Last Updated: November 28, 2009

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 in This Module

For the latest feature information and caveats, see 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 for Integrating NAT with MPLS VPNs" section.

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

Contents

Prerequisites for Integrating NAT with MPLS VPNs

Restrictions for Integrating NAT with MPLS VPNs

Information About Integrating NAT with MPLS VPNs

How to Integrate NAT with MPLS VPNs

Configuration Examples for Integrating NAT with MPLS VPNs

Where to Go Next

Additional References

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

To integrate NAT with MPLS VPNs, you should understand the following concepts:

Benefits of NAT Integration with MPLS VPNs

Implementation Options for Integrating NAT with MPLS VPNs

Scenarios for Implementing NAT on the PE Router

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.

Figure 1 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 (optional)

Configuring Inside Static NAT with MPLS VPNs (optional)

Configuring Outside Dynamic NAT with MPLS VPNs (optional)

Configuring Outside Static NAT with MPLS VPNs (optional)

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 all VPNs being configured.

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

7. Repeat Step 6 for all VPNs 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)# ip 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

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)# ip 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

This section provides the following configuration examples:

Configuring Inside Dynamic NAT with MPLS VPNs: Example

Configuring Outside Dynamic NAT with MPLS VPNs: Example

Configuring Inside Static NAT with MPLS VPNs: Example

Configuring Outside Static NAT with MPLS VPNs: Example

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

To learn about NAT and configure it 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

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

RFCs 1
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

Table 1 lists the features in this module and provides links to specific configuration information.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.


Note Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.

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.

The following sections provide information about this feature:

"Information About Integrating NAT with MPLS VPNs" section

"How to Integrate NAT with MPLS VPNs" section