Natting with mpls connection clarification required

[Raja_D]

Hi,

I want to perform natting with mpls connection in place. will it be possible ?

Suppose if i have natting in place over my CE router how could we configure the bgp configuration with PE from CE, how does the service provider play a key role in this..

please advise. Connectivity setup image is enclosed.  

[Hitesh Vinzoda]

Hi James

For NAT, you need to define ACL to match the traffic which needs to be natted.

As your WAN facing interface to the provider is excluded from NAT ACL, you can run BGP using provider supplied ip subnet.

HTH

Hitesh

[Raja_D]

Hi Hitesh, 

Let assume that I have PAT in place and i will be translating the actual ip to a specific pat ip as per the same given below:

ip access-list standard 1

10 permit 10.2.20.0 0.0.0.255

ip nat pool lab 172.16.24.3 172.16.24.3 netmask 255.255.255.252

ip nat inside source list 1 pool lab overload

With above config in place my actual lan pool will get translated to one single ip of 172.16.24.3 for any request that comes from the source lan pool 10.2.20.0/24 and my CE router will have a wan ip which i will configure it as given by the provider. 

But as its mpls connection how do i advertise my lan pool and which ip pool or ip do i need to advertise from my CE end so that the PE of the provider will further advertise in their mpls cloud ?

please clarify. 

[Hitesh Vinzoda]

Hi there,

There are two ways of doing it.

1. Create a static route for larger subnet towards null0 or with higher AD and redistribute in PE to CE routing protocol

2. Elegant way of doing it is create a new loopback and then advertisement in the routing protocol or redistribute it.

HTH

Hitesh

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[Raja_D]

Hi Hitesh,

I am sorry I could not get to understand, can you help to represent the same with the ip pool and nat configuration that i have provided based on the image that is shared..

Thanks in advance..

James..

[Hitesh Vinzoda]

ip access-list standard 1

10 permit 10.2.20.0 0.0.0.255

ip nat pool lab 172.16.24.0 172.16.24.3 netmask 255.255.255.252

ip nat inside source list 1 pool lab overload

int loopback1001

ip address 172.16.24.1 255.255.255.252

Advertise 172.16.24.0/30 in the PE-CE protocol.

HTH

Hitesh