Troubles with outgoing TCP connections

Hello!

I was experiencing serious problems with web-browsing on this one
machine -- various sites would sometimes be very slow or timeout
altogether.

A Windows machine on the other desk is plugged into the same
NAT-router going over to the same cable modem. It is running the
same version of Firefox and has no problems whatsoever.

Actually, the browser can be ruled out as the cause -- even the
following simple script

	while (1)
		date
		fetch -o /dev/null http://www.FreeBSD.org/
		sleep 0.5
	end

hangs every 5-8 cycles (the fetch process usually stays in "connect"
state for a minute or so and then times out).

I also noticed, that ssh-ing out from this machine is broken :-(
The outgoing connection abruptly closes all the time.

I went through the kernel config file and removed all the IPSEC and
IPFW stuff, as well as VFA_AIO. The problem still exists.

This box was my main machine for years -- running 4.x and 5.x fine.
After rebuilding it with 6.0 I'm stuck with this mistery. Any hope?

If you wish to look around -- contact me privately for an account.
Inbound connections seem fine.

Thanks!

	-mi