coa.duckburg.dk has one IP number , but the reverse is lrrr.inwx.net. ckt.de, suby.de, inwx.com, inwx.net, diggr.de and at least 100 other hosts point to the same IP. duckburg.dk is a domain controlled by three nameservers at inwx.de. All of them are on different IP networks. Incoming mail for duckburg.dk is handled by one mailserver having a total of two IP numbers. They are on the same IP network. duckburg.dk has one IP number. coa.duckburg.dk is hosted on a server in Germany even though the hostname implies Denmark.