ext-ns01.covad.com has one IP number , but the reverse is ns1.covad.com. ns1.covad.com point to the same IP. covad.com is delegated to four nameservers, however three extra nameservers are listed in the zone. All nameservers are at covad.com themselves. Some of them are on the same IP network. Incoming mail for covad.com is handled by two mailservers also at covad.com. They are on the same IP network. covad.com has one IP number. ext-ns01.covad.com is hosted on a server in United States.