ipmasqadm portfw ..doesn't quite work right

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Author: Rusty Carruth
Date:  
Subject: ipmasqadm portfw ..doesn't quite work right
>
> Hey all,
>     Ok, I have a problem.  My objective is to forward my firewall port 26 (not 
> used) to an internal port 22 (ssh).  My problem is that it didn't work.  Here 
> is basically what I did..


> So I have some questions.
> - Did I implement ipmasqadm portfw correctly?


I'm using ipchains, so I cannot comment on that, but here's how I'm curently
doing it with ipchains:

 ipchains -A input -v    -i $extint -p tcp    -d 0.0.0.0/0 25 -j REDIRECT 123
 ipchains -A input -v    -i $extint -p udp    -d 0.0.0.0/0 25 -j REDIRECT 123
# not sure I need this:
 ipchains -A input -v    -i $extint -p tcp      -d $extip/32 25     -j ACCEPT
 ipchains -A input -v    -i $extint -p udp      -d $extip/32 25     -j ACCEPT


> - Does the machine on 192.168.1.100 have to be configured in any particular
> way to handle this?


You do need to make sure that port 26 is allowed to pass through. Do a port
scan from outside the machine and see if that port is open.

Also, don't forget the really useful 'netstat -a' command when tryin to diagnose
things like this!

rusty