dns2.siel.si has one IP number , which also has a corresponding reverse pointer. 213-239-221-138.clients.your-server.de point to the same IP. p2p.si, kam.si, p-s.si, had.si, ruby.si and at least 100 other hosts use this as a nameserver. siel.si is a domain controlled by three nameservers at siel.si themselves. All of them are on different IP networks. Incoming mail for siel.si is handled by one mailserver also at siel.si. siel.si has one IP number , but the reverse is dns1.siel.si. dns2.siel.si is hosted on a server in Germany even though the hostname implies Slovenia.