Incoming mail for www10.pipni.cz is handled by one mailserver at pipni.cz. www10.pipni.cz has one IP number , which also has a corresponding reverse pointer. cmsg.cz, dirs.cz, dja75.cz, emris.cz, d-os.net and at least 100 other hosts point to the same IP. www10.pipni.cz use this as a mailserver. pipni.cz is a domain controlled by three nameservers also at pipni.cz. Two of them are on the same IP network. Incoming mail for pipni.cz is handled by two mailservers also at pipni.cz. They are on different IP networks. pipni.cz has one IP number , but the reverse is ns.pipni.cz. www10.pipni.cz is hosted on a server in Czech Republic.