[sllug-members]: DHCP & DNS Issues

[Justin R Findlay]

On Fri, Jun 16, 2006 at 06:47:37PM -0600, Elijah Newren wrote:
> Hi everyone,
> 
> For some reason, my sister's laptop (running FC5, if relevant) isn't
> setting the default gateway when using DHCP to determine network
> settings.  I told her the workaround was to manually run e.g.
>  route add default gw 192.168.0.1
> whenever she boots up or restarts her network.  This manual
> intervention is somewhat annoying, and it strikes me as really odd
> that no default gateway is being set.  This was probably caused by
> people at her work doing some modifications to her laptop to give her
> whatever static configuration she needed there, but somewhat
> embarassingly I can't find what would cause this.  This has happened
> with two different DHCP servers and in both cases my laptop (also
> running FC5) has no such problems with the same network.

Although it feels like a hack you could put

route add default gw 192.168.0.1

in /etc/rc.local.  A real redhat and/or DHCP guru would be capable of
giving you a real answer here.

> There is also a second issue, that I think may have come up on this
> list before but which I don't remember the answer to.  The Qwest
> Actiontec modem, acting as a DHCP server, will always provide two
> nameservers -- the first is 192.168.0.1 (itself), which doesn't work,
> and then the second is the legitimate one.  With the bogus nameserver,
> the network connection seems to move at a crawl.  One can workaround
> this by editing /etc/resolv.conf to remove the incorrect line each
> time, but that's somewhat annoying.  Is there any way to configure
> things to just automatically ignore  the bad nameserver and not use
> it?

I've had problems with qwest provided routers acting as nameservers.  My
solution so far was to move the entry for the real nameserver to the top
of the file and then save it as
/etc/resolv.conf.the_real_thing_not_the_one_the_stupid_qwest_router_misconfigured
and then again put something in /etc/rc.local like:

cp -f /etc/resolv.conf.blah_blah /etc/resolv.conf

My guess is that when you have the wrong nameserver at the top it has to
timeout somehow before moving on to the next one in the list.


Justin