So I've run into a problem using local DNS resolution with Sophos UTM 9.313.
The network is 1 internal subset ( 192.168.55.0/24 ) and has four external IP addresses. The web server is located at 192.168.55.25. In order to support applications that require websockets, I have used one of the four external IP addresses as a passthrough ( we'll call it xx.xx.xx.xx on port 80 / 443 are routed / NAT / firewalled directly to 192.168.55.25 ) and another external IP ( say yy.yy.yy.yy ) is setup with WAF applications.
Here's the issue: When using local DNS entries, Sophos appears to assign wildcard matching status even when no wildcard is specified. Thus, the setup is seen as:
computer.name.local
Reverse DNS -> Checked
Additional Host names:
domain.name
www(dot)domain.name
sub1.domain.name
sub2.domain.name
sub3.domain.name
All of these domains are hosted on the external IP that points directly to the webserver ( xx.xx.xx.xx ), so in order for them to work internally ( due to the routing issues mentioned elsewhere on these boards ) internal DNS must be configured ( preferred ) or a full NAT setup to allow proper redirection.
The domains all work fine, until you try to access the WAF on the alternate external IP address ( yy.yy.yy.yy ). Then things go bad. For example, I type in sub4.domain.name which is hosted on yy.yy.yy.yy instead of xx.xx.xx.xx, and my browser tells me it cannot resolve the domain. Okay, odd, start troubleshooting. The problem goes away as soon as I remove the non-sub address.
In other words, the host entry now looks like:
computer.name.local
Reverse DNS -> Checked
Additional Host names:
www(dot)domain.name
sub1.domain.name
sub2.domain.name
sub3.domain.name
Now, both xx.xx.xx.xx and yy.yy.yy.yy hosted domains work, but on the internal network I can no longer resolve domain.name. The easiest solution would be to setup domain.name and www(dot)domain.name on the WAF so that both resolve, but the WAF still does not support websockets in 2015 without modifications that do not persist across reboots of the Sophos UTM ( see
here regarding feature requests about websockets ). Another solution would of course be to setup an actual dedicated internal DNS server, but that seems pretty heavy handed for what I require ( only a few addresses ).
I guess my question then is, is this the expected behaviour? Is not including a a subdomain in the DNS resolution of Host objects on a Sophos UTM supposed to be the same as specifying a wildcard address?