calypso.urec.cnrs.fr has one IP number , which also has a corresponding reverse pointer. iap.fr, cnrs.fr, urec.fr, ibpc.fr, archi.fr and at least 100 other hosts use this as a nameserver. grenoble.urec.cnrs.fr use this as a mailserver. urec.cnrs.fr is a domain controlled by four nameservers. All of them are on different IP networks. Incoming mail for urec.cnrs.fr is handled by one mailserver having a total of two IP numbers. They are on the same IP network. calypso.urec.cnrs.fr is hosted on a server in France.