[TriLUG] OT: DNS/Routing Curiosity

David A. Cafaro dac at trilug.org
Mon Jul 26 21:48:01 EDT 2004


Simple answer:  It's probably a difference in your firewalls at home and
at work.  I've had several occasions where a one firewall has no problem
routing back to the external IP (a cheap netgear router doing port
forwarding to an internal host for webservices) while a more
"commercial" firewall (a significantly more expensive sonicwall router
doing port forwarding to an internal host for webservices) would not.  

Best bet is to double check the configs on the router at work to see if
you are missing some setting to allow internal users to be redirected
back to your own network.

Cheers,
David

PS.  And yes at the time there was good reason to allow port forwarding
through the sonicwall to an internal machine, we were trying to test a
theory in a controlled situation (well almost controlled didn't know
about the port forwarding limitation till then)

On Mon, 2004-07-26 at 16:51, Brian Henning wrote:
> Hi List,
>   Been meaning to toss this question out there and see if anyone would
> enlighten me..  Here's the scoop:
> At home, I can, for example, type in http://cheetah.dynip.com on any
> computer inside my home LAN and get my website.  cheetah.dynip.com points to
> my DSL external IP.  So apparently, packets for that particular connection
> go outbound, then turn around at the nearest external router to find their
> way to my server.
> At work, however, the same trick doesn't seem to work.
> http://strutmasters.net doesn't come back around to our server; it just
> never gets answered.  From outside it works as expected.
> What could be the difference?
> Is that enough info to explain what I want to know?  I'll be happy to go
> into greater detail if necessary.
> 
> Cheers,
> ~Brian
> ----------------
> Brian A. Henning
> Strutmasters.com
> 866.597.2397
> ----------------
-- 
David A. Cafaro
dac(at)trilug.org
Admin to User: "You did what!?!?!"




More information about the TriLUG mailing list