NAT allocation during a pool configuration.

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NAT allocation during a pool configuration.

L3 Networker


We have a NAT pool configured for one of the ongoing requirements. Is there a way to force this pool to allocate IP address from start to end as per new requests come in?


e.g. NAT pool configured is to

IP source is anything between to


We noticed that if the traffic source is it could take an IP from anywhere in the NAT pool. I want to force it to take a first IP in the pool.


Also is it possible to configure something which keeps the last octet static? (this may be too much to ask.)






Cyber Elite
Cyber Elite


So essentially regardless of the source IP in that range, you want the firewall to NAT with the first available IP in the pool? That really isn't how the NAT process on the firewall is designed, and I'm not sure you'll be able to get this to work at all. 

L7 Applicator


Maybe I do not understand your question, but as long as your effective source and your source NAT IP range are the same soze, then you could use static NAT...


My understanding of the question was that it didn't matter what the source IP was within the given range, the NAT was desired to be the first unused NAT address within the given range. 

I agree though for something like this a simple static NAT rule would be a bit more resonable as you are mapping 10 different source addresses to 10 different NAT addresses and I presume using Dynamic IP. If a static NAT was setup then you would know exactly what address what going to get which NAT address and you wouldn't have to worry about the way the Dynamic IP process chooses a NAT address out of order. 

L7 Applicator


I admit, I never configured it with 10 addresses. But when I used a /24 or /25 as source IP and the same network size as source NAT, the last octett remained the same.

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