Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

PAT v/s Global NAT Pool

Hi there,

Can anyone tell me if there is a performance difference in configuring PAT vis a vis setting up glbal nat against a pool of public addresses.

More specifically, we have 5 public ip addresses at our disposal which can be used to NAT internal addresses on our Pix firewall.

We are presently using PAT to allow internet access.

Would there be any difference in performance if I use these 5 addresses in a global pool for NAT in conjunction with a PAT.




Re: PAT v/s Global NAT Pool

There would be no noticable performance difference between using PAT solely and a combination of NAT and PAT. The PIX really does not care if the address is from a pool or a single overloaded address. Unless you have a specific issue you are trying to address by adding in the 5 addresses for the pool, I would advise that you just hang on to these addresses in case you need to create some static NAT entries later on. Adding in 5 addresses to a NAT pool really buys you nothing from my perspective. It just means the first 5 xlates through the PIX will get a 1:1 NAT address and all others will be overloaded to the one PAT address as you currently do it.

Hope this helps.


New Member

Re: PAT v/s Global NAT Pool

Hi Scott,

Thanks. That answers my question.

My question was more academic in nature than trying to address a particular issue.



CreatePlease to create content