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New Member

NAT ovelap

Hi,

is anybody using nat overlap, if so how to use this practically.

for example i have two 192.168.1.0/24 networks connected by leased line.

after nat overlap configuraton, how to identify particular system on particular system?

is NAT overlap really useful? if so how with one example?

Regards

skrao

3 REPLIES
Purple

Re: NAT ovelap

Hi,

When you have an overlap NAT situation, both sites would be using a separate address block

to identify systems at the other site. This could be done statically but is a bit

unwieldy. More often, what would happen is that when site A wishes to communicate with a

host in site B (which has an address from the same network), the incoming DNS response is

translated by site A's NAT device so that the Site B address is now from a different

range. When the site A host now sends a packet to this address, it's own source address

will be translated to a different address block. That way, unambiguous connectivity will

result.

There's a good diagram describing this here:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hiad_c/ch20/ntbaddrs

.htm#wp1070492

Pls do remember to rate posts.

Paresh

New Member

Re: NAT ovelap

hi paresh,

thanks for your response, but the link you have given is not working.

is there any facility to configure NAT like this.

two networks having 192.168.1.0/24 address.

I want to translate like this.

192.168.1.0/24 to 192.168.2.0/24

that means 192.168.1.1 becomes 192.168.2.1

and 192.168.1.2 becomes 192.168.2.2 and so on consecutively................

is there any such one-to-one NAT for ranges mapping facility?

Regards

skrao

Purple

Re: NAT ovelap

Here's that link again:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hiad_c/ch20/ntbaddrs.htm#wp1070492

To answer your second question: yes, there is such a facility and it's called static network translation. You would configure it as such:

ip nat inside source static network 192.168.1.0 192.168.2.0 /24

With the above config, 192.168.1.1 becomes 192.168.2.1, 192.168.1.2 becomes 192.168.2.2 and so on....

Pls do remember to rate posts.

Paresh

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