Red Hat Knowledgebase

Some networks require  access to external servers to be explicitly defined for security purposes.  Restricted proxy servers or firewalls, for example, can be configured to allow access to RHN servers for automatic updating with up2date or yum update.  This makes it unnecessary to store passwords or other authentication information in RHN configuration files.

To allow unrestricted access to Red Hat Network's update servers, configure your proxy or firewall to allow access to the following servers:

https://xmlrpc.rhn.redhat.com:443
http://xmlrpc.rhn.redhat.com:80
https://rhn.redhat.com:443
http://rhn.redhat.com:80

This will allow up2date or yum to contact Red Hat Network without interference from proxies or firewalls.