mail2.ak3.net has one IP number , but the reverse is b19.banan.cz. ivl.cz, banan.it, ovsem.net, mail2.un.cz, s2.banan.cz and at least 100 other hosts point to the same IP. ak3.net use this as a mailserver. ak3.net is delegated to two nameservers, however one extra nameserver is listed in the zone. Two of them are on the same IP network. Incoming mail for ak3.net is handled by two mailservers at ak3.net themselves. They are on the same IP network. ak3.net has one IP number. mail2.ak3.net is hosted on a server in Czech Republic.