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New Member

nat

can anyone help me, I have a site with 2 routers, 1 connects to head office 1 the other connects out to another office 2, the head office 1 has an ip of say 172.19.50.1, the head office one has a lan ip of 172.19.50.2 and another interface on the 10.1.1.1 network, These are natted across on router 2 to look like 172.19.50.x addresses, my question is do i need a route on the 172.19.50.1 router to get to these natted pc's on the other router ?

4 REPLIES

Re: nat

Hello Carl,

me again.

I guess this question demands another question.

If you are NATting the 10.x.x.x address to 172.19.50.x addresses I would think that there's no route to network 10.0.0.0/8 on the first router right?

so, 10.0.0.0 would not be visible to router 1.

If you are doing static NAT 1x1 devices connected to router 1 would simply go to 172.19.50.x to reach those machines on router 2.

Im not sure this is 100% accurate, but hope it helps.

anyway again good link for NAT issues:

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a008044eddc.html#wp1045853

Please rate my posts

Vlad

New Member

Re: nat

I wanted to know really if I needed a route on router 1 to get to the natted pc's on router 2, the issue is that router 1 has the same lan ip as router 2 so how will it know how to get to these hosts even though really they have been translated to 172 address range.

Re: nat

Hello Carl, your router 1 should already have this route, as it has an interface configured on this subnet.

If you are using an ip like 172.19.50.1/24 on interface serial 1, router 1 will have a route on its routing table like:

C 172.19.50.0/24 is directly connected, Serial1

So, you wont need to manually configure this, and hosts would appear in the ARP table of router1, like you said they are on the same LAN (same subnet).

Hope this helps,

please rate my post!

Vlad

New Member

Re: nat

so how does router 1 know they are real hosts, does the nat router advertise them out, I would of thought that a route would of still needed to be put on to forward the 172.19.50 traffic to this router even though I know its on the same network ?

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