mail.gtg.hr has two IP numbers. They are on the same IP network. mail.gkm.hr, mail.hwt.hr, mail.052.com, mail.lebi.net, mail.balic.hr and at least 99 other hosts point to the same IP. gtg.hr use this as a mailserver. gtg.hr is a domain controlled by two nameservers at paranid.net. They are on different IP networks. Incoming mail for gtg.hr is handled by one mailserver having a total of two IP numbers. They are on the same IP network. gtg.hr has one IP number. mail.gtg.hr is hosted on two servers in Germany even though the hostname implies Croatia.