Company computer need access to the internal network through corporate network DNS application system, at the same time need to group the DNS access group company network application system as well as through telecommunications access to the Internet, so computer matching three DNS, whatever order set of DNS, frequently visit group network application system can't access problems, PING url can parse out the IP address of the right, but can't access, if you remove the other two DNS, immediately can access, plus two other DNS at this moment, still can normal visit, but over time, and will be unable to access, please expert advice,