[K12OSN] domain name loops back to dsl router

Jim Kronebusch jim at winonacotter.org
Wed Jun 21 13:03:58 UTC 2006

> > I have a strange one here, or so it is to me. I setup another 4.4.1
> > K12LTSP box at my house. I got my own domain name for this box,and what
> > is
> > happening is, when i enter my domain name locally the browser winds up
> > redirecting to the dsl modem/router interface that i have from the dsl
> > provider.
> > This is not actually redirecting to ip address of the server ,it is the
> > ip
> > assigned to the router. I have disabled all port forwards trying to
> > reslove it, but still same thing. I am guessing it is something maybe i
> > have setup on the dns provider( easydns). But i surely cant get it
> > figured
> > out:(. I have to vnc to a machine outside my lan in order to make sure
> > for
> > example my home page is working or mailman etc.
> > The website comes up fine on a remote machine so it appears to be
> > working
> > correctly, I can also email fine, with this domain name.

I am not sure I am a 100% clear on this but here is a shot.  I'll assume the
following are correct:

-You have a domain name registered with yourdomain.org pointing to your
external static IP address (the one assigned to your router)
-Your router has an entry to take requests from the outside world and direct
them to the proper inside port (Port forwarding external port 80 requests on
external IP to internal port 80 on internal IP)
-You do not have external Admin turned on in your router also listening on
port 80 and interrupting your external requests
-It sounds like externally (from outside your NAT'd network) the domain name
and port forwarding work fine and get where they are supposed to go

If the above is all correct and you still hit the router interface when trying
your domain name internally, I believe it is your router that is the problem.
 I have found that some routers are "smarter" than others.  Some newer routers
and most higher end routers (Cisco, Linux) are able to see a request from an
internal IP directed towards an external IP and know enough to pass it through
the router to the outside world and then re-enter the local network thus
following proper port forwarding.  Some routers do not.  If you happen to have
one of the "dumber" routers the best fix I have found is what Eric said.  I
either build an internal DNS server or modify all hosts files on my machines.
 If you only have a couple of machines the hosts files work fine, if you have
a few hundred it is a real time saver to setup the internal DNS and setup your
dhcp server to hand out your internal DNS instead of the ISP's, and on your
static boxes do the same.  This will give you centralized DNS management and
also the new ability to setup internal only DNS entries.  I usually opt for
the DNS server just because I have gotten fairly efficient with BIND.  

Hope that helps.

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