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In my network, I can not access servers by their public IPs from the LAN that those public IPs are NAT'd to.

For Example:

.:F0/0 (192.168.1.0/24)|RouterA|F1/0 (12.12.12.0/24):.

Lets say Server A is 192.168.1.2 and has public address of 12.12.12.2. If from Workstation 192.168.1.5 I try to access 12.12.12.2 -- that is what doesn't work (I can access it with the private IP fine of course, and fine using the public IP from another network). Is this normal, or is there perhaps something abnormal about by NAT config, or maybe missing something on my ACL?

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If there is no obvious answer I will post a simplified version of the NAT config a little bit later. –  Kyle Brandt Mar 1 '10 at 20:45

2 Answers 2

up vote 1 down vote accepted

You're looking for "hairpin NAT". A lot of NAT implementations don't support it. Linux iptables NAT does, for example, but many versions of Cisco IOS and PIXOS do not.

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That sounds normal and I believe it has to do with the NAT order of operations.

http://blog.internetworkexpert.com/2008/02/15/the-inside-and-outside-of-nat/

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