dns resolution exceedingly slow

greeklegend · 10-19-2006, 02:14 AM

Hi all,
Previously, i had a perfectly functioning ubuntu 6.06 system. However, recently i purchaced a second computer, and therefore had to put a router in between the modem and my existing PC.
This seems to have made dns resolution very slow indeed; i'm on 256kb/s and it takes anything up to 15 secs to find the IP of a name with ping.
However, it resolves at a normal speed when i use "host".
Any ideas?

andrewdodsworth · 10-19-2006, 03:03 AM

Things to check depending on how the router is set up are that on Ubuntu machine what the default gateway is set to (normally the router) and what nameserver is in /etc/resolv.conf (should be ISP's nameserver or any other public nameserver).

If this is okay then best bet is to run ethereal on Ubuntu to see where the DNS queries are going.

Another possibility is IPv6 - a long while back with SuSE 9.x it was trying IPv6 DNS lookups first before IPv4. This gave similar symptoms.

greeklegend · 10-19-2006, 03:23 AM

Ahh brilliant thankyou.
My /etc/resolv.conf file had my modem and then my router as dns servers. I changed these to my ISP's dns servers and it's all good
Thanks Andrew!