topic Re: FMC Platform Settings in Network Security

FMC Platform Settings

benolyndav — Fri, 24 Jan 2025 13:16:05 GMT

Just wondered if any new that if I added DNS servers to the DNS group in platform settings that this is disruptive, I;m only adding additional Servers.??

Also is adding NTP Servers on FMC disruptive at all.?

Thanks

Re: FMC Platform Settings

MHM Cisco World — Fri, 24 Jan 2025 13:24:20 GMT

I dont get your Q

Can you more elaborate

MHM

Re: FMC Platform Settings

benolyndav — Fri, 24 Jan 2025 13:26:47 GMT

@MHM Cisco World In platform settings for devices in FMC, we have a DNS group in the DNS option, if I add extra servers to that DNS group is this disruptive at all I'm just adding extra servers.???

Re: FMC Platform Settings

Rob Ingram — Fri, 24 Jan 2025 13:27:21 GMT

@benolyndav Are you using the current DNS server to perform any FQDN lookups? Or time based access control rules that uses the existing NTP servers? If they are changed and it doesn't work (for whatever reason), that might cause a disruption. Assuming the DNS servers can resolve the hostnames and NTP servers are accurate, then changing those settings would be fine.

Re: FMC Platform Settings

benolyndav — Fri, 24 Jan 2025 13:29:25 GMT

@Rob Ingram Yes they are doing FQDN lookups but I am wanting to add 2 more Servers to the group I am not changing the current Servers in the group.

Thanks

Re: FMC Platform Settings

Rob Ingram — Fri, 24 Jan 2025 13:32:01 GMT

@benolyndav amending the platform settings policy settings should be fine, it doesn't cause a blip in traffic "through" the device when the policy is applied, if that was your concern.

Re: FMC Platform Settings

MHM Cisco World — Fri, 24 Jan 2025 13:46:37 GMT

I need to check the criteria fnc use to switch from one fmc to other

MHM

Re: FMC Platform Settings

MHM Cisco World — Sat, 25 Jan 2025 21:35:38 GMT

As you mention' this DNS for mgmt interface and use by FTD to resolve fqdn of ACL.

Multi DNS in group' FTD send first one if server failed to resolve then FTD will send to second DNS.

So adding new DNS will not effect fqdn resolved.

MHM

Re: FMC Platform Settings

Aref Alsouqi — Sun, 26 Jan 2025 13:13:01 GMT

Assuming the new DNS servers are reachable and functional, this change will not be disruptive. Same concept applies to the NTP servers.