FMC Migration - Derigistering Source FMC from SSM, Impact.

[danielbarri]

We will perform the steps in:
https://www.cisco.com/c/en/us/td/docs/security/firepower/fmc_model_migration/b_FMC_Model_Migration_Guide/migrate_your_fmc.html

We have below two questions regarding the impact of the step 6 in the migrations guide.

What we are wondering, is something like IPS management or something else, affected by this deregistration?

We want to know if we can deregister the source FMC during working hours or if it should be done outside regular hours, due to certain functions not working when the license is deregistered?

[Marvin Rhoads · Accepted solution]

Step 6 will only result in licensing being out of compliance. You won't be using it anymore once you move to step 7 so there's no harm done to traffic through the managed devices. In other words, it (by itself) won't affect traffic or operations of the managed firewalls.

If you delay moving on to the next steps though, things like Security Intelligence updates will stop coming in. If you use URL Filtering, lookups for non-cached entries will fail. Eventually any locally queued log messages (assuming you are logging connection events and security intelligence events to FMC) will age out and be lost.

[danielbarri]

Thanks for your input Marvin!