[Ubuntu-SG] [Slugnet] DNS on Ubuntu question

[jeff Jansen]

Martin Bähr <mbaehr at email.archlab.tuwien.ac.at> wrote on 2010-Aug-30:
> On Mon, Aug 30, 2010 at 08:23:58AM +0800, Mark Philip wrote:
>> When I check on my connection, it reports that my primary DNS is my
>> wireless router's IP address, whilst my secondary DNS is the Starhub
>> IP.
> 
> the dns servers are most likely set from your router (where your
> computer gets its ip address from)
> 
> if your routers dns is to slow i(or not responding) then maybe the dns
> settings in the router are wrong. 

I would also check your theory that the first DNS server is the slow part.  You
can use the "dig" command to query a specific DNS server and see how long it takes.

If 'dig' is not installed then install it with 'sudo apt-get install "dnsutils".

Then if your primary DNS server is 192.168.1.1, you would run

dig @192.168.1.1  www.ubuntu.com

That will ask the DNS server at '192.168.1.1' for that 'A' record for that
hostname.  There will be a line near the bottom which says

;; Query time: 27 msec

That tells you how long it took to lookup this hostname.

If it times out, then there's a problem with that server.  You can do the same
thing using your secondary DNS servers, etc. and see how long they take.

If you find a problem with your DNS settings, then make the changes in your
router.  That's where the problem is.  Just laptop is just doing what your
router told it to do.  Maybe you need to turn on the forwarding DNS server in
the router; maybe you just need to hard-code your ISP's DNS servers into your
router, etc.

But change the settings in your router, and then ANY machines that connect to
your network will get the proper DNS information and you won't have to make
these changes to EVERYONE's laptop when you invite the whole LUG over for a
Hack-a-thon. ;-)

HTH

Jeff