Use all IPs in a NAT pool before doing overload?

Unanswered Question
May 8th, 2008

I have several sites where clients have IOS routers using a NAT pool with overload. The problem is that all of the sources appears as the first IP int he pool, and it never goes on to use more IPs in the pool (because it doesn't run out of ports). Is there a way to setup a pool such that it will fill up the pool first, then start doing overload when it's full?

I have this problem too.
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tstanik Wed, 05/14/2008 - 06:06

When using a NAT pool with the overload command, only one of the pool addresses is used, not all of them are used.

Pravin Phadte Wed, 05/14/2008 - 10:19

I would not agree to tstanik.

If nat overload is done with more that one ip address it will use other ips when the pool is short of the ports.

I dont see a way of limiting the ports in the overload for single ip adress or multiple ip address range.

One way how it can be done is by spliting the nat pool ip address range.

for example if you have 2 ip address overloading. you can change the satement to one ip address for one pool and acl to nat overload and the other second one with net pool with one more acl.

for this you would require to subnet the ip address.

I would suggest to change the nat satement if you feel its not using the public ip address and use them for somthing else. Also i would not suggest to do a 2 nat pool since it uses a lot of cpu on the router.

anyone can correct me if i am wrong but ports cant be limited on nat overload.


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