ns1.google.com.vn has one IP number , but the reverse is ns1.google.com. tvojebaba.cz, ns1.google.de, ns1.google.tk, ns1.google.es, ns1.google.vn and at least 18 other hosts point to the same IP. google.com.vn is delegated to three nameservers, however one extra nameserver is listed in the zone. All nameservers are at google.com. All of them are on different IP networks. Incoming mail for google.com.vn is handled by four mailservers. All of them are on the same IP network. google.com.vn has three IP numbers. All of them are on different IP networks. ns1.google.com.vn is hosted on a server in United States even though the hostname implies Vietnam.