RedHat Edition -A Hands on Guide Prev Chapter 9. The leftmost column is the IP address to be resolved. The next column is that host's name.
Any subsequent columns are alias for that host.
After you are finished configuring your networking files, don't forget to restart your network for the changes to take effect. Time out problems for telnet or ftp connection are often caused by the server trying to resolve the client IP address to a DNS name. Either DNS isn't configured properly on your server or the client machines aren't known to DNS .