Summary
mail.btk.vn has two IP numbers. They are on different IP networks.
btk.vn,
bmv.vn,
thamtu.us,
pghot.com,
clbu30.com and at least 53 other hosts point to the same IP.
btk.vn is delegated to two nameservers, however four extra nameservers are listed in the zone. There are three duplicated IP numbers. Some of them are on the same IP network. Incoming mail for
btk.vn is handled by two mailservers on the same IP network.
btk.vn has one IP number , but the reverse is
localhost.