I recently bought a D-Link DCS-930L network webcam which is connected to my WLAN network. It retrieves a IP address via DHCP from DD-WRT based router (a TP-Link TL-WR1043ND), and it is listed under "Active wireless nodes".
The camera is registered to a webservice called "My DLink", which enables the user to access the webcam from the internet (via their webpage or via smartphone apps). This service works, and I can access the camera from outside.
However, when I try to connect from inside my (W)LAN, it says "No route to host". How is that possible?
EDIT: I found the answer by myself accidentally by skimming through the IP webcam settings. It turned out that the option Setup > Network Setup > UPnP Port Forwarding was set to Enable. I don't use UPnP in my LAN, and it is disabled on my router.
I don't understand how the enabled UPnP on the webcam could cause troubles, when there were no other devices supporting UPnP. Has anybody an explanation for this?