Please help with PF-based redirector

[Alex Povolotsky]

Hello!

I'm trying to set up a box as round-robin TCP proxy. Of course, I'm 
trying to do everything on kernel-level.

This simple setup

rdr on sk0 proto tcp from any to any port = smtp -> <outbound> port 25 
round-robin

should work. At least, I thought so.

However, attempt to connect to port 25 yielded unexpected result. pfctl 
-s state shows

self tcp 89.108.94.212:25 <- 89.108.94.91:25 <- 
89.108.94.211:56975       CLOSED:SYN_SENT

connection never established, and no IP packet ever sends out to 
89.108.94.212:25

I don't understand this thing. Maybe someone can point me to my error?

(firewall rules a quite permissive, in fact, they are pass in quick and 
pass out quick for all interfaces. attempt to telnet to port 25 outside 
works ok)

Alex.