There are the following lines in the ip-masq-mini-howto:

  # outgoing from local net on remote interface, stuffed masquerading, deny
  ipfwadm -O -a deny -V your.static.PPP.address -S 192.168.0.0/16 ...

My question is simple: what does that "stuffed masq'ing" mean and in
which situations this filtering is needed?

I'm very sorry if this is FAQ.  I couldn't find any information about
that on the Web and noone seems to know anything about that.

I'm very interested about this, 'cause a similar rule really blocked
(and logged) a few packets on my computer.  Please notice that it was
the _outgoing_ filter which blocked those packets.

The packets were going from 192.168.1.2 and going to x.y.z.w (a
machine in *.com domain, that address isn't familiar to me) via eth0.
There were something like 20 packets in about 2 minutes:

   May  5 10:53:30 narnia vmunix: IP fw-out deny eth0 ICMP/3 192.168.1.2
   x,y.z.w L=56 S=0x00 I=32935 F=0x0000 T=31

Only that I=xxxx (and, of course, the time) varied.


My configuration:

  eth0 = internet
  eth1 = local network, addresses 192.168.1.x.

The ip-masquerading is working perfectly, has worked already about one
year.  There was no other information related to this in the logs and
I've never seen anything like that.

The ipfwadm setup is based on the sample configuration of the
ip-masq-mini-howto.  There _are_ incoming filters which do filter any
packet coming from 192.168.1.x via eth0 and those filters do work.

There are only trusted users on my box.

The kernel version is 2.0.33 (+ all security patches).

192.168.1.2 really exists, it's a Win95 box and it was switched on
when this happened.  Nothing strange happened on that machine.


How is it possible that my machine generates packets which seem to be
coming from 192.168.1.2?  If they were really coming from that
address via eth1, they would be masqueraded.  If they were coming via
eth0, they would have been blocked.

Is this a ip-masq bug?  Or a feature?  Or a cracking attempt?  Or am I
disturbing the wrong people, can this be something compeletely
different which isn't even related to masq'ing?-)

 ---------------------------------------------------------
  Jukka Suomela                     [EMAIL PROTECTED]
   Servin-Maijan tie 10 F 83        http://narnia.tky.hut.fi
    02150 ESPOO, FINLAND                        (09) 468 2963

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