Ipfilter keep state can't handle Linux TCP window scaling 7

Hi,

I tried on FreeBSD 10 and FreeBSD 11

Linux 2.6.8 --> ipfilter/FreeBSD 4.10 -> FreeBSD 5.4

ssh from Linux to FreeBSD 5.4 with rule on the ipfilter/FreeBSD 4.10 box
in the middle.

pass in quick on lnc0 proto tcp from 10.1.0.0/16 to 172.31.0.0/16 port =
22 flags S keep-state

The Linux box is on the 10.1.0.0 and FreeBSD 5.4 on the 172.31.0.0.

Once the Linux sets the TCP window scale to 7 (TCP option 3), the ssh
will stall and then reset under some load. The SSH login and a few "ls"
command worked fine.


Any help is appreciated.

Ming