Cisco Firepower FQDN DNS Resolving Issue - IPv6

[latenaite2011]

Hey everyone,

Does anyone know how to remove IPv6 DNS server from the DNS Trusted Source (DNS Server configured) and also any references to IPv6 when resolving FQDN on the firepower or passing through it (for data plan traffic)?  I think it might be causing some intermittent issue going across the firepower because the show dns server shows 2 IPv4 dns servers and one IPv6, which I can't seem to get rid of. I even configured a custom dns server group with just the two DNS servers and restarted the dns process in expert mode in Firepower.

TIA, 

[Marius Gunnerud]

Where are you looking for the trusted DNS source?  

These should be located in the platform settings associated with the FTD device (Platform Settings > {Platform Setting Policy} > DNS > Trusted DNS Servers)