[clug-talk] DNS woes
Carl
ct at turner.ca
Mon Apr 3 16:04:41 PDT 2006
I picked up a wired Linksys router (BEFSR81) and connected it. And it
exhibited the same problem! ie, could get Internet connectivity but no
name resolution. And when I looked at the Linksys status page the DNS
severs were set to 0.0.0.0.
I swapped the router in and out of the network a few times. And each
time with my PC connected to the cable modem directly things worked
fine. But with a router in between (either the SMC or Linksys) DNS would
not work.
So I hooked up a hub as Gustin suggested and used Ethereal to see what
was happening.
I tried both the PC and SMC router. In both cases, the client would
request DHCP Option 6: Domain Name Server. But in the Shaw DHCP response
only the responses to the PC would contain the information for Option 6.
ie. the DNS servers.
Then I tried with the Linksys router and I noticed the Shaw response did
contain DNS server info! So I put my network back with the Linksys in
place and everything worked.
So then I put the SMC router back in (which was my original setup) and
now everything is working fine.
Talk about a wild goose chase. I'm guessing Shaw had a temporary issue
with their DHCP server but now it must be resolved?
Carl
On Mon, 2006-04-03 at 14:39 -0600, Darren L wrote:
> Let me know if you find a WRT54Gv4!
>
>
>
> On 4/3/06, Carl <ct at turner.ca> wrote:
> The front end on the SMC has an option to release/renew the
> IP. Each
> time it gets the same IP though. And each time the DNS servers
> are
> 0.0.0.0.
>
> It is funny how this problem just showed up today after many
> months of
> using the SMC router.
>
> Anyway, since the problem is likely in the SMC firmware I
> think I'll
> just go out and purchase a new router. As you say it is
> probably not
> worth my time to trouble shoot. I am somewhat curious but if I
> can't end
> up fixing the problem it will just frustrate me. One of the
> big
> downsides of using a closed source appliance.
>
> Thanks,
>
> Carl
>
>
>
>
>
> On Mon, 2006-04-03 at 13:21 -0600, Gustin Johnson wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Does the management front end on the SMC have an option to
> release and
> > renew the dynamic IP that Shaw assigns? If this does not
> populate the
> > DNS servers on the SMC router, then the problem is likely an
> error in
> > the SMC firmware. Unless there is an updated firmware, you
> may be
> > better served by buying a new router (I have a couple of
> linksys
> > wireless routers and a couple of linux boxes with different
> distros that
> > all work fine with Shaw, so you have a lot of choice here).
> >
> > Trouble shooting this is not really worth the time, since
> you can't fix
> > the problem (The SMC is a closed appliance that you do not
> have access
> > to). If buying a new $80 router fixes the problem, then it
> is not even
> > worth 1 hour of my time to troubleshoot.
> >
> > Of course if you are curious then it is worth the time. It
> would be
> > interesting to see the differences between the linux box and
> the SMC,
> > but from a curiosity/educational point of view, not really a
> technical
> > troubleshooting point of view.
> >
> > Ethereal is a neat tool, especially if have/are
> reading/learning about
> > TCP/IP (Shawn, my review of that giant TCP/IP book should be
> ready this
> > week).
> >
> > An old fashioned hub is great in this case, since it repeats
> packets to
> > all ports, making it easy for Ethereal to capture them (ie
> cable modem
> > to hub, then both the linux box and SMC router to the hub).
> >
> > Cheers
> > __
> >
> >
> > Carl wrote:
> > > My home network has decided to stop resolving names today.
> Eg. If I ping
> > > google.com I get unknown host yet if I ping 64.233.167.99
> I get
> > > responses. If I enter host google.com I get:
> > > ;; connection timed out; no servers could be reached
> > >
> > > I have several computers connected to an SMC router which
> is connected
> > > to a Shaw cable modem. The computer I have using now is
> running Fedora
> > > core 3.
> > >
> > > While connected through the SMC Barricade router
> my /etc/resolv.conf is:
> > >
> > > ; generated by NetworkManager, do not edit!
> > > search cg.shawcable.net
> > > nameserver 192.168.2.1
> > >
> > > If I browse to 192.168.2.1 on the status page, among other
> things I see:
> > >
> > > Primary DNS: 0.0.0.0
> > > Secondary DNS: 0.0.0.0
> > >
> > >
> > > If I connect my computer directly to the cable modem
> things are good,
> > > name resolution works and and my /etc/resolv.conf looks
> like:
> > >
> > > ; generated by NetworkManager, do not edit!
> > > search cg.shawcable.net
> > > nameserver 64.59.135.133
> > > nameserver 64.59.135.135
> > >
> > >
> > > To me it seems like the SMC router is not getting the DNS
> information
> > > correctly from the Shaw DHCP server. I phoned Shaw and
> they said it is a
> > > problem with my SMC router. I talked to SMC tech support
> and they got me
> > > to manually enter the DNS servers and then it works. I
> don't want to
> > > have to manually setup the DNS config but they offer no
> other solution.
> > >
> > > Does anyone know why the SMC router might have trouble
> receiving the DNS
> > > info? How can I trouble shoot this? Would using Ethereal
> to see what is
> > > happening be worthwhile?
> > >
> > > Thanks,
> > >
> > > Carl
> > >
> > >
> > >
> > >
> > >
> > >
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