Hiya, I've noticed something for a while now and I thought I'd finally post about it and see what folks think. Basically, my linode has very slow DNS resolution, lately especially. I never paid much attention before, even though I had Apache set to resolve hostnames for the log files. There were times I'd notice slowness, but I thought it was just the linode being taxed. Recently however my website began responding very poorly, and by pure luck I happened to put it together that it was in fact slow DNS causing the whole website to drag (from resolving everyone's IP for the log file), so for the time being I have hostname resolution disabled in Apache's config, so the site is at least running well again.

Here's what my /etc/resolv.conf looks like:

search members.linode.com
nameserver 64.5.53.6
nameserver 12.96.160.115
nameserver 216.234.234.30

Something I noticed is if I comment out 64.5.53.6, DNS seems to run speedy again, but I assume the DHCP client is replacing this every so often because it comes right back and DNS resolves poorly again. Does anyone have any idea why, or what I can do to permanently fix it? Thanks in advance.

I had noticed this as well, due to long connect times in postfix. I installed bind9 (gotta love Debian) and things are a bit smoother, but the first lookup is still a problem. I don't know what distro you are using but in Debian you can override the settings dhclient gives you in /etc/dhclient.conf. Just add this line to the file:

supersede domain-name-servers 12.96.160.115, 216.234.234.30;

The problem is that you'll be out of luck if Linode changes the DNS server's IP.

Maybe caker or mikegrb can give more info or change the DHCP settings to move 64.5.53.6 down in the list?

Cheers,
Brian

Well spotted! have also been noticing some slow downs which are related to slow DNS resoloution.

A couple of dig requests to 64.5.53.6 reveal that its down, or at least unreachable from host52. I tried renewing my DHCP lease but this DNS server is still being given out.

The other two are working fine, so I've just removed the one in question from resolv.conf. Hopefully caker/mike will fix this soon...

I raised a ticket, was told it was fixed. A little later it actually was fixed, but now its happening again!

64.5.53.6 resolves to host1.linode.com, which is clearly up, but I still can't run DNS queries against it, just times out...

Is anyone else having this problem? I'm going to raise another ticket.

I used bkirkbri's suggestion and added the supersede command to dhclient's configuration, but then I wasn't sure how to get it to reload its config without restarting the whole networking system, so I tried a SIGHUP on it, but that only managed to kill the process. lol. Oh well. For the time being, at least, that DNS server won't be coming back for me!

I have services running and would rather not disrupt active connections unless necessary, so I'll just leave it for now. In the meantime I'm sure they'll get this worked out.