Most companies these days restrict their internet access by forcing the usage of web proxy. If your company is forcing a proxy policy & you are running Redhat/CentOs/Fedora you will have to update your yum.conf to be able to update your desktop or server using yum over a proxy connection. Luckily setting up yum to run over a proxy is an easy task. below is the few steps you need to follow to establish just that.

Edit the file /etc/yum.conf and add the following lines:

  # The proxy server - server: port
  proxy=http://proxy.mydomain.com:3128
  # If proxy authentication is required
  proxy_username=yum_user
  proxy_password=yun_user_password 

The next step is to declare the variable http_proxy to run
when the yum rpm get executed to avoid the below error:

warning: rpmts_HdrFromFdno: Header V3 DSA signature: nokey, key
ID e8562897