DHCP and Cox Cable

[Jeffrey Pyne]

There are a few ways to do this.  Here's what I do (well, here's what I do
when those f***ers at Cox see fit to have my connection up).  I run Apache
on port 80 on my internal web server.  I used to have my firewall redirect
incoming requests for port 80 on my public IP address to port 80 on my
internal "private" IP address.  But then, several months ago, Cox started
blocking inbound requests on port 80 for my segment.  So I changed my
firewall a bit.  It now redirects inbound port 8192 (or some random port I
picked-- I would check if those f***ers at Cox would see fit to have my
connection up) to port 80 on my web server.  OpenBSD's firewalling allows
you to do this.  I don't know if you can do that with a Linux firewall or
one of those LinkSys routers.

To get around the DHCP thing, I use Zone Edit (www.zoneedit.com) to host my
DNS, which is free.  I set up a URL forward at Zone Edit (which can handle
forwarding to different ports).  So, for example, you can have
http://www.yourdomain.com get "forwarded" to
http://zippy.yourdomain.com:8192.  You can even set it up so that it does
this "transparently" (i.e. the URL in your browser never changes).  Then, as
the last piece of the puzzle, you just need to dynamically update DNS for
zippy.yourdomain.com.  You can run a command like this in cron every so
often:

wget -O - --http-user=username --http-passwd=password
'http://dynamic.zoneedit.com/auth/dynamic.html?host=zippy.yourdomain.com' 

which dynamically updates zippy.yourdomain.com in Zone Edit's DNS to
whatever IP address originated the connection to the URL in that wget
command.

So www.yourdomain.com would get translated to zippy.yourdomain.com:8192 by
the URL forward, which would get translated to <yourDynamicIP>:8192 by
Dynamic DNS, which would get translated to <yourInternalIP:80> by your
firewall.  Whew!

There are probably other ways to do this, but this is what I do and it works
well for me (when those f***ers at Cox see fit to have my connection up,
that is).  

Did I mention that my Cox connection has been down for the last day+ ?

HTH,

~Jeff

On Wednesday, January 23, 2002 Mark Phillips wrote:

> I am hoping you can help me with a small problem with my Cox service.
>
> I have a web server behind my firewall and I used to be able to access it
> because I had a fixed IP. I switched over to the new Cox service, and Cox
is
> changing my IP address. Is there anyway to get to my web server through my
> firewall on a consistent basis? I use the server for projects and need to
> access it from the road. I am not a networking expert, so I am not sure
how
> to do this.
>
> I can't use the web pages provided by Cox because I have servlets running
> with JSP, EJB, etc. on the server.
>
> Thanks!
>
> Mark Phillips