relay1.nedcomp.nl has one IP number , which also has a corresponding reverse pointer. relay1.zwemvaardigheid.nl cnames to this hostname. ski.be, a-b.nl, iak.nl, nha.nl, hvh.nl and at least 100 other hosts use this as a mailserver. nedcomp.nl is delegated to two nameservers, however one extra nameserver is listed in the zone. All of them are on different IP networks. Incoming mail for nedcomp.nl is handled by four mailservers at nedcomp.nl themselves. All of them are on the same IP network. relay1.nedcomp.nl is hosted on a server in Netherlands.