mail.upg.ch has one IP number , via cname to ns0.ovh.net , which also has a corresponding reverse pointer. mail.itg.gp, pop3.nyu.ch, smtp.nyu.ch, mail.nyu.ch, mail.web2.cc and at least 100 other hosts point to the same IP. upg.ch is a domain controlled by two nameservers at ovh.net. They are on the same IP network. Incoming mail for upg.ch is handled by two mailservers also at ovh.net. They are on the same IP network. upg.ch has one IP number. mail.upg.ch is hosted on a server in France even though the hostname implies Switzerland.