Is there a difference between a NAT pool & static NAT

darrenriley5 · ‎04-17-2009

Is there a slight difference between using a NAT pool & static NAT? Reason I ask is I've had a problem with a couple of printers which were NAT'd using a NAT Pool. The printers are based at one of our branches. Sometimes I can ping them from my PC using the NAT address while other time I can't. If a change them to use a static NAT I never experience this problem.

John Blakley · ‎04-17-2009

Static NAT is generally one-to-one, whereas a NAT pool sets aside a pool from a set number of addresses. When traffic is used from a nat pool, the address is used for that session until it times out (traffic stops going across from the originating host). Then the next time traffic goes out from the same host, it might be natted to a different address for the new session.

Here's a link for a better explanation:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094e77.shtml#difference

HTH,

John

HTH, John *** Please rate all useful posts ***

Jon Marshall · ‎04-17-2009

Darren

In addition to John's answer.

It's important to understand that it is not a slight difference at all but quite a large one.

static NAT sets up a permanent entry in the NAT translation table. The original IP will always be translated to the same NAT IP, every single time.

nat pool is not a permanent entry in the NAT translation table. It is a dynamic entry that is created on the fly. So there is no guarantee that the original IP will always be translated to the same NAT IP.

Static NAT and dynamic NAT are used for different purposes.

Jon