Proxy authentication settings are set properly in the /etc/apt/apt.conf and even in the network settings. But the sudo apt-get update command gives an error "something wicked happend in resolving proxy. (-5 - no hostname attached ) . This happens only with the connection in my room. It works normally with the internet connection in my friends room. But again the strange thing is, I have a windows 7 alongside ubuntu 12.04 and the proxy settings are working properly in windows (even with my room's connection). Any help could be appreciated. Thanks in advance..
Please verify that the line in the /etc/apt/apt.conf is in the following format:
This is including the ; on the end, and the quotes on each end of the address. You could shorten it to the following when no authentication is necessary.