I too am unable to view WMS 1.1.0 or 1.3.0 inside of ArcMap 10.2. Both my GetMap and GetCapabilities work in a browser and I can view the the images inside of MapServer for Windows. They are being served by Apache so my situation is a little different.
The problem is the same though, that the images are not being displayed inside ArcMap.
A GetCapabilities request is being sent to MapServer successfully from ArcMap. There is not record in the logs
of a GetMap request being sent at all.
Richard