mail.k28.org has one IP number , but the reverse is mail.pipni.cz. mail.uk.cz, mail.190.as, mail.3am.cz, mail.c-4.cz, mail.1dz.cz and at least 100 other hosts point to the same IP. k28.org use this as a mailserver. k28.org is delegated to two nameservers, however one extra nameserver is listed in the zone. All nameservers are at pipni.cz. Two of them are on the same IP network. Incoming mail for k28.org is handled by two mailservers on different IP networks. k28.org has one IP number. mail.k28.org is hosted on a server in Czech Republic.