Firewall Adjustment - Allow SFTP from DNS Name

[Zydain]

I received the following request:

pLease make a Firewall Adjustment to ADD the Following DNS Names for each area: 

• HTTP, HTTPS

•      xx.example.com, yy.example.com, zz.example.com

• SFTP=Port 22

•      files.example.com

When looking at the firewall rules, it looked like I could only do IP addresses, and not DNS names.  I only looked at the GUI though.  Am I able to perform these tasks via DNS name instead of IP with the Cisco ISR 4321?

[balaji.bandi]

    HTTP, HTTPS

         xx.example.com, yy.example.com, zz.example.com

    SFTP=Port 22

         files.example.com

is this resolves with fixed IP ? or the IP changes ?

what IOS XE code running on Cisco ISR 4321.