Having a classic problem where one of our websites is not accessible inside the building.
IIS server sitting on a DMZ.
I've setup split-brain DNS, so internally DNS points to the internal IP of the webserver and configured the appropriate Firewall rules to allow HTTPS.
DNS is resolving fine, firewall rules are triggering, but the website doesn't load.
When we surf the website externally it works fine.
When we surf the site using it's internal IP from inside it works… but not when using the DNS entry.
DNS resolves to the correct IP, that tells me this is an IIS problem. Just have no idea where to look.
(double, triple, and quadruple checked the DNS, because it's almost always DNS but doesn't seem to be the case here?)
Source: r/sysadmin · by /u/DarkAlman