ns3.hmco.com has one IP number , which also has a corresponding reverse pointer. ns2.spider-bridge.com point to the same IP. hmco.com, rigby.com, catinc.com, mlmath.com, harstz.net and at least 100 other hosts use this as a nameserver. hmco.com is a domain controlled by three nameservers at hmco.com themselves. All of them are on different IP networks. Incoming mail for hmco.com is handled by two mailservers also at hmco.com. They are on different IP networks. hmco.com has one IP number. ns3.hmco.com is hosted on a server in United States.
