Running Home-based mail server, but ISP blocks port 25?

[Steven W. Orr]

On Mon, 16 Dec 2002 pll at lanminds.com wrote:

=>
=>Hi all,
=>
=>Some one was inquiring how they can run a mail server on a port other 
=>than port 25.  They're DNS is hosted by some third party, and their 
=>ISP blocks all ports < 1024 incoming to the cable modem.
=>
=>Is there some way to specify a port address in DNS?  How else would 
=>you let the world know your mail server isn't where is should be?

The only thing I can think of is that your nameserver is capable of 
performing some sort of port redirection. e.g., I run with RCN which 
blocks port 80. My nameservice is done via zoneedit.com which provides a 
service to forward to a different port. So I run apache on port 8080 and 
http://www2.syslang.net/ and zoneedit forwards 
http://www.syslang.net/ --> http://www2.syslang.net:8080/
In the case of RCN, they provide webforwarding but not a generalized port 
forwarding service.

The point is that it has to be done at the nameserver level, since there's 
no way to tell everyone in the world that you're listening on something 
other than port 25. 

Also, it's somewhat understandable that their claim is that you should not 
be running a server. OTOH, I think they're probably also preventing you 
from playing any peer-to-peer games.

-- 
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-individuals! What if this weren't a hypothetical question? steveo at syslang.net