Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

When I ping the server, I get this output:

PING ( 56(84) bytes of data.
64 bytes from ( icmp_req=1 ttl=50 time=35.7 ms
64 bytes from ( icmp_req=2 ttl=50 time=38.1 ms
64 bytes from ( icmp_req=3 ttl=50 time=34.6 ms

Domain name does not match. What does it mean ?

share|improve this question
up vote 11 down vote accepted

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 first must be translated to, then a PTR request can be made. You can see this in the detailed output of the dig command:

$ dig -x

; <<>> DiG 9.8.1-P1 <<>> -x
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21897
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;    IN  PTR


;; Query time: 148 msec
;; WHEN: Sat Jan 26 08:47:32 2013
;; MSG SIZE  rcvd: 82
share|improve this answer

If you run dig, you will get the IP (normal lookup request).

If you run dig -x, you will get the name (reverse lookup request).

That's it.

share|improve this answer is simply the reverse DNS name for It only means, that the domain name your pinging is not the reverse DNS for the IP. Nothing more.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.