mx1.cybion.fr has one IP number , but the reverse is mu-in-f27.1e100.net. 1e.ca, mx2.z51.fr, sagaci.com, mx2.ctrl.it, g.mx.vntx.net and at least 100 other hosts point to the same IP. cybion.fr use this as a mailserver. cybion.fr is a domain controlled by two nameservers at amen.fr. They are on different IP networks. Incoming mail for cybion.fr is handled by seven mailservers at cybion.fr themselves. There are two duplicated IP numbers. Some of them are on the same IP network. cybion.fr has one IP number. mx1.cybion.fr is hosted on a server in United States even though the hostname implies France.