Manually opening TCP ports

[Michael R. Head]

On Fri, 2008-03-07 at 08:02 +0000, Siraj Shaikh wrote:
> Hello
> 
> I am just wondering if there is a utility (or any feature in
> ubuntu/Linux) that allows me to manually open a TCP port on a machine.
> I am looking for a way that could either allow me to open ALL or many
> TCP ports on a machine.
> 
> Also, is there any way of running a service on more than a single
> port, or on all or many ports?

After reading the rest of the thread, it appears to me that the best
solution would be to forward the ports you want to listen on to your
application. This can be done with iptables. For example, if you want to
forward all ports from 1 to 1024 to your server (which might be running
at 31337), then you could do it thusly:

for (( PORT=1; PORT<=1024; PORT++ )); do
  sudo iptables -t nat -A PREROUTING -p tcp --dport $PORT  -j DNAT --to 127.0.0.1:31337
done


   

> Thanks
> 
-- 
Michael R. Head <burner at suppressingfire.org>
http://www.core.binghamton.edu/~burner/new/resume.html
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