Using differing SSL certificates for WebAdmin and user Portal

Question

Good evening Community, 
 I am a relativley new user of Sophos UTM. I have managed to manually install an Let's Encrypt certificate for the WebAdmin & User portal and that works fine. Next Step, automating this. 
 However, in order to get to the Webadmin, you have to be on the internal site of the UTM. From there it has a different server name. 
 So the Let's Encrypt certificate is gw.domain.no while the internal servername is gw.domain.local. 
 What I would like to implement is, that the Webadmin uses by AD CA certificate for gw.domain.local and the User Portal uses the Let's Encrypt Certificate. Is there a way of accomplishing this? 
 Thank you for your answers! 
 B/R 
 maul0r

BAlfson · Accepted Answer

Look up "split DNS" to see that this is an accepted practice. A big advantage is that laptop users don't need two different FQDNs depending on whether they're inside the LAN (physically or via VPN) or out on the Internet. 
 You're right that you must add to your Forward-Lookup Zone for domain.no an A-record for each public FQDN that should resolve to the same thing internally and externally. 
 Cheers - Bob