Problem with route-to option

[Shaymardanov Rushan]

Hello. I have a problem using pf in Freebsd 9.0.
I'm using frebsd box as gateway and I have 2 ISP. I'd like to route some
clients via second provider and a'm using pf's route-to fuction for it:

( ... )
nat on ng0 inet from 172.18.100.254 to any -> xx.xx.xx.157
(...)
pass in route-to (ng0 10.0.0.1) inet  from 172.18.100.254 to any tag SUBS
(...)

Packets are routed correctly (via ng0), and nat works well, but IP checksum
is bad and I don't receive any response:

gw# tcpdump -i ng0 -s 0 -v -n icmp
tcpdump: listening on ng0, link-type NULL (BSD loopback), capture size
65535 bytes
18:11:54.456027 IP (tos 0x0, ttl 128, id 218, offset 0, flags [none], proto
ICMP (1), length 60, bad cksum 9390 (->9093)!)
    xx.xx.xx.157 > 8.8.8.8: ICMP echo request, id 3993, seq 171, length 40
18:11:59.480968 IP (tos 0x0, ttl 128, id 219, offset 0, flags [none], proto
ICMP (1), length 60, bad cksum 9290 (->9092)!)
    xx.xx.xx.157 > 8.8.8.8: ICMP echo request, id 3993, seq 172, length 40
18:12:04.506907 IP (tos 0x0, ttl 128, id 220, offset 0, flags [none], proto
ICMP (1), length 60, bad cksum 9190 (->9091)!)
    xx.xx.xx.157 > 8.8.8.8: ICMP echo request, id 3993, seq 173, length 40

Without route-to (if for example I change routing table for particular
destination address), checksums are good and traffic passes correctly.


Rushan Shaymardanov