When I ping the server sip3.voip-centrex.net, I get this output:
PING sip3.voip-centrex.net (194.98.81.144) 56(84) bytes of data.
64 bytes from mpfrrelay.michaelpage.fr (194.98.81.144): icmp_req=1 ttl=50 time=35.7 ms
64 bytes from mpfrrelay.michaelpage.fr (194.98.81.144): icmp_req=2 ttl=50 time=38.1 ms
64 bytes from mpfrrelay.michaelpage.fr (194.98.81.144): icmp_req=3 ttl=50 time=34.6 ms
Domain name does not match. What does it mean ?
Best Answer
The DNS system has many kinds of records. "A" records map names to IP addresses. "PTR" records map IP addresses to names. The mapping is not always transitive, and there can be multiple A records that map the the same IP address.
Strictly speaking, PTR records map special names to other names. The IP address 194.98.81.144 first must be translated to 144.81.98.194.in-addr.arpa, then a PTR request can be made. You can see this in the detailed output of the
dig
command: