/etc/resolv.conf is good but DNS is not working

**darthspacey** · 02-08-2005, 02:27 AM

Using Knoppix 3.6, booted straight off the CD with no customisations

DHCP correctly gives my machine an IP address, and the correct default route, and correctly populates /etc/resolv.conf

I can "dig" the name servers (not with any kind of finesse, but I can at least connect to them), and I can ping hosts inside and outside of my LAN by using IP addresses. However, when I try to ping by hostname, it fails to resolve the name to a number and fails with "unknown host".

I have not found the first few pages of Google results helpful. What troubleshooting steps would you recommend next?

<edit>

You wanna hear something odd? I jusyt tried booting again to see if I could gather any other useful data, and I *can* resolve (i.e. ping by name) a.root-servers.net through m.root-servers.net, but still no other hosts that I've tried.

</edit>

Thanks for your time,

**pureone** · 02-08-2005, 11:52 AM

i would try some trouble shoting with ethereal if i was you. what happens when you try to ping www.google.com does it say host not found. if it did say host not found then i would guess you wouldnt beable to surf the web at all. if you can surf the web then i guess your resolve is actuly working but it may need a few attempts to reslove the host.normaly i find with in lans pinging via host names does not always work 100% correctly

**tom p** · 02-08-2005, 04:55 PM

Hi,

what does /etc/resolv.conf look like, then?

Thomas

**darthspacey** · 02-09-2005, 02:51 AM

Originally Posted by tom p

what does /etc/resolv.conf look like, then?

One "search" line, and three "nameserver" lines, just as a resolv.conf should. The domain name is correct (at least, it matches my ISP), and I can ping, traceroute and dig all three nameservers listed. FWIW, the same box with Win2K has no (apparent) problems.

Pureone suggested using ethereal to see exactly what is being requested and when. I suppose it's plausible that the dig mechanism is independent of -- and in my case not as broken as -- the method ping uses, but I thought they both relied on the same calls. FWIW, on this subject "host" doesn't work either.

I'm supposed to be doing a college assignment right now, though, so I can't be as useful as perhaps I should be...