3

If you can't ping an ip address since you are not resolving a canonical name this has nothing to do with dns and only has to do with the inability to reach that machine (routing) right?

Improve this question
1
  • 1
    Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin ♦
    Aug 11, 2017 at 4:38

3 Answers 3

Reset to default
6

You are correct in that if you ping an IP address you are not using DNS. If you are using a hostname instead of an IP address with ping, then you will be using DNS.

However, just because you are using ping with an IP address, even if you don't get a response this does not necessarily mean there is a routing problem. Many hosts are configured to rate limit ICMP echo requests (i.e. ping) or to ignore them entirely.

Improve this answer
4

Correct.

DNS is a service which resolves a name to an IP address. If you are not pinging a name, you aren't using DNS.

Improve this answer
0

"PING" on a Windows 7/8 machine will attempt to perform a "Reverse DNS" lookup on the IP address before attempting a PING. It's reverse DNS because you are doing the reverse of what DNS natively does, i.e. resolve a name to an IP address. But that is just a feature to help identify what you're pinging.

PING still uses the IP address to formulate its echo request. The inability to perform the reverse DNS does not preclude the ICMP echo request to be sent, nor does it prevent the echo reply to come back if there is one.

Hope this helps.

Improve this answer
4
  • 1
    Do you have anything to back up this answer? It may be true in certain circumstances, by my Windows 7 does not do a reverse lookup when pinging an IP address. Verified with captures from both the computer and a span port on switch.
    – YLearn
    Feb 23, 2015 at 20:10
  • This is not the case when using an ipaddress as argument to ping.
    – Joffrey
    Feb 26, 2015 at 15:55
  • Good catch. I think this behavior changed between Windows XP and Windows Vista/7/8. I just tried it and my statement is incorrect.
    – Magic Man
    Mar 10, 2015 at 20:00
  • Looks like you now need the "-a" switch to resolve an IP address to a hostname when using ping.
    – Magic Man
    Mar 10, 2015 at 20:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

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