smtp.fdp.ch has one IP number , but no corresponding reverse pointer. smtp.rmr.ch, smtp.cck.ch, smtp.plr.ch, smtp.rod.ch, smtp.plrf.ch and at least 100 other hosts point to the same IP. fdp.ch and prd.ch use this as a mailserver. fdp.ch is a domain controlled by two nameservers on different IP networks. Incoming mail for fdp.ch is handled by one mailserver at fdp.ch themselves. fdp.ch has one IP number. smtp.fdp.ch is hosted on a server in Switzerland.