Some things to check:
1. Check that you are listening at the IP of your network card and not on 127.0.0.1
2. Activate the firewall and check if the packets of your college get blocked.
3. Take a packet sniffer and check if you can receive the packets with it.
#1) Could you elaborate on this point a bit? I create a UDPClient reciever that listens on port XYZ. I didn't specify a host address (although I could without any difficulty...perhaps I'll give this a shot - maybe it's defaulting to listen on 127.0.0.1 or something)
Update #1: I looked into this a bit more, and found the following documentation: http://msdn.microsoft.com/en-us/library/35e07es2.aspx
This constructor creates an underlying Socket and binds it to the port number from which you intend to communicate. Use this constructor if you are only interested in setting the local port number. The underlying service provider will assign the local IP address. If you pass 0 to the constructor, the underlying service provider will assign a port number. If this constructor is used, the UdpClient instance is set with an address family of IPv4 that cannot be changed or overwritten by a connect method call with an IPv6 target.
Maybe this is the problem! I'll update this again with my findings after I test it.
Update #2: I tested it again, specifying a listening host address set to my public IP, but still no luck. I performed this test while directly connecting to my modem to avoid any problems that my router might introduce. I also checked the traffic with Wireshark and noticed that the packets were being sent correctly, with the correct address and port, however, I was being informed by the ICMP that the destination was unreachable (port unreachable).
#2) I'm on a home network right now, so there shouldn't be any problem with certain packets getting blocked
#3) I have Wireshark, but I'm a bit inexperienced with it. I'll look into it though.