Issues with internal domain name when using Web Protection

Question

Hello. 
 
 I followed this best practice: https://www.sophos.com/en-us/support/knowledgebase/120283.aspx to setup my DNS using my AD DNS server aswell. Issue im having now is, when i goto an internal webserver like http://system it wont work, i get an error from sophos "host not found". When i goto http://system.local.domain it works fine. Im not sure why this is, can anyone help/explain? 
 
 Thanks!

vilic · Accepted Answer

UTM will not automatically add domain suffix to DNS searches. Try with bypassing proxy for http://system or defining static Host object definition on UTM.

rsenio · Answer

Add the "search domain" option to your UTM. Either way, you should bypass your proxy for your internal hosts as well 
 
 Web Protection - Filtering Options - Misc 
 
 Search Domain - Search domain: You can add an additional domain here, which will be searched when the first DNS lookup returns no result ("NXDOMAIN"). Then, a second DNS request is initiated which appends the domain given here to the original hostname. Example: A user enters http://wiki , meaning to address wiki.intranet.example.com. However, the URL can only be resolved when you enter intranet.example.com into the Search domain field.