Impact to active sessions when we change a firewall NAT policy

[skuo2020]

We are going to change a source and destination NAT policy.  Assuming the related security policies are in place for both the before and after change connections, are we going to see impacts to those sessions that have been active before the NAT change?

For example, the NAT is to change connection source and destination from (10.1.1.1 to 10.11.11.11) to (10.2.2.2 to 10.22.22.22). Now the NAT is changed from (10.2.2.2 to 10.22.22.22) to (10.3.3.3 to 10.33.33.33). Will the connections from (10.1.1.1 to 10.11.11.11) that have been active before this change keep working (based on the existing sessions in the session table)?  In other words, will firewall immediately purge all the related sessions affected by that NAT change?

[reaper]

if you have session rematch enabled the existing sessions will be re-evaluated against the rules after each commit

if existing sessions need to persist you'll need to turn that off before making the change

[skuo2020]

Thanks for the reply. It sounds logical but the session rematch documentation says it is for "security policy". Is "NAT policy" also part of the rematch?