В продолжении тему вот что получилось(НАТ в pf.conf):
lan_net = "192.168.15.0/24"
int_if = "em1"
ext_if2 = "re0"
ext_gw2 = "xx.xx.xx.xx"
set limit states 128000
set optimization aggressive
nat pass on em0 from 192.168.11.0/24 to any -> em0
nat pass on re0 from 192.168.15.0/24 to any -> re0
pass in on $int_if route-to { ($ext_if2 $ext_gw2) } from $lan_net to any keep state
нифига не работает tcpdump на re0 молчит. на em1
tcpdump -i em1 host 192.168.15.2
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on em1, link-type EN10MB (Ethernet), ca