ipfw+dummynet - TCP connections fail

[Puiu at Xentra]

Hi,

I have a small LAN behind a FreeBSD box connected to internet.
I have installed pppoe+freeradius to give access to internet to computers
from the LAN, everything works fine.
I decided to setup ipfw+dummynet for traffic shaping and here a 
problem occurs. If I set up even a single pipe without anything else
the TCP connections doesn't work anymore. For e.g. :

ipfw -q add pipe 1 ip from any to any in via rl1
ipfw -q pipe 1 config bw 512Kbit/s

this causes all TCP connections to fail ( although existing TCP connections
are still working, I can't initiate new TCP connections )

also tried :

ipfw -q add pipe 1 ip from any to 84.247.XX.0/24 in via rl1
ipfw -q pipe 1 config bw 512Kbit/s

same thing happends.

ipfw -q add pipe 1 ip from any to 84.247.XX.0/24 in via tunX
ipfw -q pipe 1 config bw 512Kbit/s

this works, but it is not useful since I have to shape the traffic
from the external interface and not the one from a single ppp
tun interface ( one user )

queues doesn't work either :

ipfw -q add 000400 pipe 1 ip from any to any in via rl1
ipfw -q pipe 1 config bw 512Kbit/s

ipfw -q queue 1 config pipe 1 weight 10
ipfw -q add 000401 queue 1 ip from any to 84.247.XX.YY/32

this also causes TCP connections to fail.

84.247.XX.00/24 - the network fro which IPs are provided to the
LAN computers when they are connecting to pppoe
rl1 - the NIC that connects to internet
tunXX - interfaces for the connected users.

Looked everywhere, but I haven't found any answer.
I have used ipfw+dummynet in another LAN ( without pppoe ) and
it works fine.

Any ideas please ?

Regards,
Puiu Hrenciuc.