We pick l.root-servers.net, one of the 13 root servers (1), and ask it about cybion.fr and learn that fr is delegated to five name servers (2), so we ask e.ext.nic.fr where we learn that cybion.fr is delegated to two name servers, including ns2.amen.fr (3), so we ask that one and get the following answer:
Cybion.fr is a domain controlled by two domain name servers at amen.fr. Both are on the same IP network. Incoming mail for cybion.fr is handled by three mail servers at cybion.fr themselves having a total of 36 IP numbers. There are two duplicated IP numbers. Some of them are on the same IP network. Cybion.fr has one IP number (91.121.8.101), but the reverse is ns37877.ovh.net.
