topic Fallback NAT in Network Security

Fallback NAT

Fartingdragon — Sun, 12 Mar 2023 19:17:25 GMT

I am learning about NAT for Cisco ASA and the topic talks about Fallbac NAT where I believe if I'm understanding correctly you can point the traffic from the inside to use the outside interface to translate to and traffic out once they run out of the public address pool.

But I may be misunderstanding. How does this work? Does it start using PAT or how does the ASA and the outside traffic know where to go inside if they only use the outside interface to translate?

Re: Fallback NAT

balaji.bandi — Sun, 12 Mar 2023 20:48:24 GMT

I think you understand somehow correctly.

example :

if you have a range of IP addresses take the example of Public IP range x.x.x.1 x.x.x.5 - if they are fully used, then it will use the interface to do Translation.

example of syntax

nat(inside,outside) dynamic blahbla interface

Re: Fallback NAT

MHM Cisco World — Sun, 12 Mar 2023 20:54:34 GMT

I think you talk about using Pool of public IP in NAT,
this NAT use first interface in Pool and if the interface exhausted it will NAT to second IP in Pool

Re: Fallback NAT

Fartingdragon — Sun, 02 Apr 2023 22:37:36 GMT

To anyone reading this, Fallback NAT does end up using the WAN address after it runs out of IPs and uses ports with the WAN. Thanks for all that relied.