If your system is behind a ISA proxy you need to do the following to get yum to work properly.
Step one: Download the cntlm rpm package
For 64 Bit CentOS 6.x
ftp://rpmfind.net/linux/epel/6/x86_64/cntlm-0.35.1-4.el6.x86_64.rpm
For 32 Bit CentOS 6.x
ftp://rpmfind.net/linux/epel/6/i386/cntlm-0.35.1-4.el6.i686.rpm
Step two: Install the rpm package
For 64 Bit
rpm -ivh cntlm-0.35.1-4.el6.x86_64.rpm
For 32 Bit
rpm -ivh cntlm-0.35.1-4.el6.i686.rpm
Step three: Edit /etc/cntlm.conf
vi /etc/cntlm.conf Username userxxx #Domain Account Domain example.com #Domain Name Password uiuzdf7/d #Password Proxy 192.168.1.1:8080 #ISA Proxy
Save and quit
:wq
Step four: Make sure that cntlm now were the confi file is by typing:
cntlm -c /etc/cntlm.conf
Info about the switch -c:
cntlm -c
Configuration file. Command-line options, if used, override its single options or are added at the top of the list for multi options (tunnels, parent proxies, etc) with the exception of ACLs, which are completely overriden. Use /dev/null to disable any config file.Step five: Edit yum.conf
vi /etc/yum.conf
proxy=http://127.0.0.1:3128/
Save and quit
:wq
Step six: Edit bash profile
vi .bash_profile
Add the following lines :
export http_proxy=http://localhost:3128/
export https_proxy=${http_proxy}
export ftp_proxy=${http_proxy}Save and quit
:wq
Step seven: log off and login again
logout or exit
Step eight: Run the command yum clean all to clear yum
yum clean all
Step nine: install the package you like
yum install <package name>
You can check out more information about yum: