NETWORKING=yes HOSTNAME=totosh.ampoliros.net GATEWAY=192.168.0.254
# DNS FDN nameserver 188.8.131.52 nameserver 184.108.40.206
This is about associating and IP address with a domain name. It usually depends on your access provider, since they provide you with an IP address.
My internet access provider for totosh is currently Free SAS. The reverse DNS setup is described at http://www.free.fr/assistance/248.html.
To check the rDNS:
$ host 220.127.116.11 18.104.22.168.in-addr.arpa domain name pointer totosh.ampoliros.net.