natd -redirect_port

[patrick]

Dongxiang Liao wrote:
> Hey there,
> 
> I have been playing with ipfw and natd to setup firewall and port remap, 
> but having problem with a seemingly trivial situation.
> 
> I want to redirect the incoming traffic to port 995 to port 22 on the 
> same machine.  The man page of natd suggest natd -redirect_port should 
> do it.  But "natd -redirect_port tcp 22 995" indicate I am missing the 
> target address and alias address.  I don't quite understand the 
> situation since I have only one machine itself here.
> 
> I would appreciate any suggestions.
> 
> Dong
> 


Assuming you already setup "natd" and it's working then the following 
should work, provided your internal network/interface is numbered 
192.168.1.1 and your external network/interface 1.2.3.4.
redirect_port tcp 192.168.1.1:995 1.2.3.4:22

I have feeling you are attempting to make the pop3 access secure, if 
yes, take a look at:
http://www.cs.duke.edu/csl/security/secure-email.php

Regards,
Patrick Soltani.