Firepower Management Center effect registration of managed devices?

[evan.chadwick1]

Hi, 

I have a solution that has been rolled out that has an incorrect hostname of the manager FMC on each managed SFR.

When performing a show module sfr I do get the correct ip address for the FMC.

First question :

1/ is the name of the FMC locally on each managed SFR arbitrary? My ASA show output reveals the sfr sees the correct ip address for our FMC. But our SFR currently has an incorrect hostname due to an incorrect/old dns record at time of configuration

For eg

From ASA CLi

show module sfr detail

<snip>
DC addr: X.X.X.X (correct ip)

<snip>

logged in to the sfr module

session sfr console

> show managers
Type : Manager
Host : incorrect.name.com  (that no longer resolves to the correct ip above)
Registration : Completed

Second Question

Can I change the hostname of a FMC without effect registration to all the managed devices or the SSL certificate? The company wants to use firepower.internal.different.com

For eg,

FMC hostname is currently

firepower.name.com

dns for its ip is now

firepower.internal.different.com

The SSL certificate currently refers to CN of firepower

[Jetsy Mathew · Accepted solution]

You can change the hostname by using the following command :-

> configure network hostname ABCDEF

            Its better to re-register the device once again. When you register the device , it will automatically create a UUID between the Firesight and Firepower to maintain the communication channel. In your case if the UUID is the hostname and if you change the hostname  after the device registration then it may result in communication channel connectivity issues.

[evan.chadwick1]

I re registered them all a few days ago and that sorted it out.