Scenario: I connect through a Network Proxy to get to the Internet. This proxy requires a username and password for authentication.

Problem: "apt-get install bla bla" in shell results in error "407 proxy authentication required"

Things I tried: 1. system---> Network proxy (enter correctly)-->Details (Entered Authentication Username and Password there)

2. vi /etc/apt/apt.conf ---> Acquire::http:roxy "http://usernameassword@<proxy_ip>:<proxy_port>/";

this last one worked yesterday and apt was able to connect to the Internet but today I restarted and it doesn't work now.

Please point out what I'm missing. Thanks.