[TriLUG] Questions on dyndns.org

Mike Mueller mjm-58 at mindspring.com
Thu Oct 3 14:48:06 EDT 2002


On Thursday 03 October 2002 12:27, Jeremy Portzer wrote:
> On Thu, 2002-10-03 at 11:57, Mike Mueller wrote:
> > I am researching this right now too.  Port forwarding on the firewall/NAT
> > seems to be the thing to do from what I've read so far.  Port 80 (httpd)
> > might be blocked on your ISP so you may need to get the dynamic dns to
> > translate port 80 to some other port number.
>
> Huh?  DNS is responsible for changing the hostname to an IP address.  It
> has nothing to do with port numbers.   NAT/masquerading firewalls can
> change port numbers, but that's unrelated to DNS.
>
> And do any ISPs really block port 80?  I think that's more of a myth
> than reality.

Evidently it is a reality.  Enough so that dyndns.org offers a method to work 
around the limitation. I don't know if it's the case with Earthlink Cable, 
but as I said in my post I am researching the details right now.  Here is 
where I learned about the possibility of port 80 being blocked: 
http://support.dyndns.org/guides/portredirect.php

As for changing port numbers, anything device or application between 
origination and destination can change a port number.  It's only a value in a 
field in the IP header.


-- 
mueller, mike

The larger purpose of the economic order, including Wall Street, is to 
support the material conditions for human existence, not to undermine and 
destabilize them.

-Editorial, The Nation, August 19, 2002



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