pf synproxy slowdown

[Anders N.]

Hi. I've got a server running pf that has been displaying some odd (at least to me) behavior.

I use the "synproxy state"[1] option quite a few times in my config without any ill effects that I've noticed until now. I realized it was on every open port except for ssh, so I added it to my ssh line:

pass in on $ext_if proto tcp from any to $IP port 22 flags S/SA synproxy state

After doing so, scp/sftp/rsync have all slowed down to a crawl! I get ~1/4th the speed I usually do from the server with it enabled there. Remove it, speed goes back to normal. I'm using synproxy state with some other other services that send large amounts of data very quickly (http, torrents, etc) and none of them exhibit this slowdown, so I'm wondering why scp is so slow with it. Here's the rest of my pf.conf, if it matters:


ext_if = "bge0"
set block-policy drop
scrub in all
block in all
block in quick on $ext_if from any to 255.255.255.255
pass out on $ext_if from any to any
pass out keep state
set skip on lo0
block in quick from urpf-failed
antispoof quick for $ext_if
block in from no-route to any
block drop in log (all)  quick on $ext_if from { 10.0.0.0/8, 172.16.0.0/12, 255.255.255.255/32 } to any
block drop out log (all) quick on $ext_if from any to { 10.0.0.0/8, 172.16.0.0/12, 255.255.255.255/32 }
block in quick on $ext_if proto tcp flags FUP/WEUAPRSF
block in quick on $ext_if proto tcp flags WEUAPRSF/WEUAPRSF
block in quick on $ext_if proto tcp flags SRAFU/WEUAPRSF
block in quick on $ext_if proto tcp flags /WEUAPRSF
block in quick on $ext_if proto tcp flags SR/SR
block in quick on $ext_if proto tcp flags SF/SF
pass in on $ext_if proto tcp from any to $IP port 22 flags S/SA synproxy state
pass in on $ext_if proto tcp from any to $IP port 80 flags S/SA synproxy state
pass in on $ext_if proto tcp from any to $IP port 9999 flags S/SA synproxy state

I'm not on the list, so please CC me if it's not too much trouble.

[1] http://www.openbsd.org/faq/pf/filter.html