reverse DNS lookup

mimithebrain · 06-05-2006, 01:39 PM

Just curious, is linux suppose to do a reverse DNS lookup for each ping I send to google?

unSpawn · 06-06-2006, 06:58 AM

AFAIK not if results are cached. Persistent caching nameserver: Pdnsd.

mimithebrain · 06-06-2006, 10:55 AM

ah, so in the case of my ubuntu, it's normal.

The only problem I see with it is that puts a load on the router (having internal DNS chaching thingy). Hence, when the router doesn't answer with the reverse lookup, the ping are not sent until it does come back.

It doesn't ask for reverse lookup if I'm pinging google's IP instead of "google.com"
Is there a place where I can adjust this behavior?

that looks like a nice program, pdnsd, I bookmarked it

thanks

unSpawn · 06-08-2006, 05:53 AM

It doesn't ask for reverse lookup if I'm pinging google's IP instead of "google.com"
No, that's because of how resolving hostnames works.

Is there a place where I can adjust this behavior?
AFAIK, no.

mimithebrain · 06-08-2006, 08:18 AM

Well, I learn something new everyday.

I go to bed at night less stupid then the night before.

thanks unSpawn

EvilC0P · 06-08-2006, 08:28 AM

for the reverse lookup, ping doesnt care about machine's name.
thats how the IP works, with IP adresses, numbers.

names are for us, human , easier to remember a name/word than a bunch of numbers.

so if you ping a name, dns gives the machines the IP then the ping proceeds.
never it will try to do reverse lookup for his own use. he doesnt use it...
just tho i would clarify a lil detail.

vimal09 · 02-10-2011, 12:53 AM

You can use this http://www.whoisxy.com/ reverse dns lookup tool .It's free service.