I am running ubuntu 14.04. Recently I am not able to update the apt source. When I typed "sudo apt-get update", the process is very very slow, in hours that not proceed. And the result is all "Ign" or "Err" except one get "Get:1 http://mirrors.aliyun.com trusty Release.gpg [933 B]". But my colleague's ubuntu 14.04 is ok with this command and it installs software or updates the source.
I've tried many source from officer to locally, but the result is the same.
How to solve this problem?
I've tried more than 5 apt sources ,but both failed to update or install.their ip or website I've tested and all is ok (ping or use web browser).Download debs from the source directly(wget) is ok.
I run ubuntu in virtualbox and can access internet and the net is bridged to my pc's phyiscal net card. Two virtualbox run in my pc. Their configure of apt source is same,One can apt update and install,while one cannot.
When I open a vpn in my pc,the questioned ubuntu can apt-get update and install,then I closed vpn,it cannot update or install.