Quick and dirty ...
            ________ IPMASQADM FAQ ________  Juanjo,  16-Mar-1999

           http://juanjox.linuxhq.com/ipmasqadm-FAQ.txt

=Q:
> I just want to used portforwarding in my
> kernel 2.1.122 (using your ip_masq_portfw) but seem it doesn't work. My
> question is should I setup IP Chains first before use it?
=A:
YEAp, portfw works by reverse-masq so you must have a masq rule to
``take the reply packets out''
Eg 
If you:
   # ipmasqadm portfw -A -P tcp -L internet_IP    80 -R internal_IP 80

you should, AT LEAST, have  
   # ipchains -I forward -p tcp -s internal_IP/32 80 -j MASQ

=Q:
> 
> Perhaps a little offtopic, but has anyone had success using ipmasqadm? I 
> remember somebody saying so, but I have tried several times to no avail. I am 
> currently using 2.1.101. Before of that, I tried with 2.1.9[7-9], 2.1.100, 
> same results.
> 
> If I do:
> 
>     ipmasqadm portfw -a -P tcp -L local 1080 -R remote 80
>     telnet local 1080
> 
> it waits forever for a connection. I also use masquerading for connecting my 
> net to the internet. Tried to delete masquerading, but no success though. Even 
> tried:
=A:
portfw will only work when kernel is *forwarding* (masquerading, actually),
local sourced connections don't go via forwarder, so are (almost, he) invisible
to portforwarding.

=Q:
> Hi everyone, I just setup a linux router to masquerade my lan to the net
> and am wondering if its going to be possible to have it forward
> ports(telnet etc) to my computer which sitting on the same lan.  Running
> ipautofw gets me:
> 
> # ipautofw -A -r tcp 23 23 -h 192.168.1.1
> setsockopt: Protocol not available
> 
> 192.168.1.254 is the router box and 192.168.1.1 is me
> 
> Anyone know whats up?  Can ipchains somehow accomplish what I wan't to do
> or does it currently remain unimplemented?  Are you out there Richard
> Lynch?  netis.netis.com doesnt seem to want to deliver mail to you...
> 
=A:
For 2.1 you must use ipmasqadm (you can fetch it from my URL). For your
setup, portfw command should be something like

  # ipmasqadm portfw -a -P tcp -L <internet_addr> 23 -R 192.168.1.1 23

Please note that LOCAL redirection (ie. telnet <internet_addr> at the router)
won't work, you must use it from outside.

=Q:
> Hi,
> I tried to forward a request for  host 193.159.175.194 80 to
> 192.168.100.30 80, which is a web server. I use 2.1.112 kernel ip-masq and
> ip-masq-ipportfw enabled, the command I tried out is ipmasqadm portfw -a
> - -P tcp -L 193.159.175.194 80 -R 192.168.100.30 80 . The output of tcpdump
> looks good, but there is no connect. At that point I'm using no ip-filters
> and no masquerading, is that o.k?
> 
> Can you figure out, how to solve this problem?
=A:
Currently portfw does sortof "reverse-masq", so it does require
direct masq configured:
    ipchains -I forward -p tcp -s 192.168.100.30/32 80 -j MASQ

BTW You can see nice masq status in /proc/net/ip_masq/entries

=Q:
> > Please check that you did enable portfw in your .config
> > :
> > CONFIG_KMOD=y      
> > CONFIG_IP_MASQUERADE_MOD=y
> > CONFIG_IP_MASQUERADE_IPPORTFW=m
> > :
> 
> Do I nead any patch to use it together with my 2.1.128 kernel??
> 
> I didn't get all those options when I do a make config (or make
> menuconfig) 
=A:
Please add 
  CONFIG_EXPERIMENTAL=y
... and get ready ... 8)