I've run out of of ideas, but this seems to be an issue with VLC. I am running 2.1.5 (Intel 64bit) on OS X 10.9.5. I have three webcams (2 from D-Link and one from Belkin). I'm running PFSense as my firewall/router and DNSexit for my dynamicDNS service. Internally I can connect to all three cameras ...