NAT1:1 Multiple external IPs pointing to same internal IP

Rapture · Jan 27, 2011, 2:01 PM

Hi all,

I know that 1:1 NAT-ing from nulitple external IPs to a single internal IP is not recommended. But could someone please educate me as to why it is not a good idea.

TIA

Melvin

jimp · Jan 27, 2011, 6:53 PM

Because when traffic goes out, which IP is it supposed to use? Incoming connections may be OK, but outgoing connections would likely never use the second IP, no matter what you do.

Specific port forwards and outbound NAT rules (or in 2.0 1:1 NAT rules for different IPs but with source/destination restrictions) should be OK, but just putting two whole external IPs to the same internal IP isn't likely to be what you really want to do.

Rapture · Jan 28, 2011, 10:18 AM

Hi Jim, Thanks for the clarification. Makes perfect sense.

Melvin