mail.medwell.com has one IP number , but the reverse is localhost. ns4.de, umcn.nl, sunx.org, cabi.net, celox.nl and at least 100 other hosts point to the same IP. medwell.com use this as a mailserver. medwell.com is delegated to two nameservers, however one delegated nameserver is missing in the zone and one other nameserver is listed instead. All nameservers are at curtiscomp.com. Two of them are on the same IP network. Incoming mail for medwell.com is handled by one mailserver at medwell.com themselves.