lhrmail.nu.edu.pk has one IP number , but the reverse is sea-cr181.mx.dnspark.net. 9you.us, fass.net, bw12.com, aiaa.net, wkri.com and at least 100 other hosts point to the same IP. nu.edu.pk is a domain controlled by two nameservers at dnspark.net. They are on different IP networks. Incoming mail for nu.edu.pk is handled by seven mailservers having a total of 28 IP numbers. Some of them are on the same IP network. nu.edu.pk has one IP number. lhrmail.nu.edu.pk is hosted on a server in United States even though the hostname implies Pakistan.