It was great to see that 2.4.0 reintroduced ipfwadm support! I had noIt's working here for me - the netfilter modules are named differently:
need for ipchains and ended up using the wrapper around it that
emulated ipfwadm. However, 2.[02].x used to have "special IP
masquerading modules" such as ip_masq_ftp.o, ip_masq_quake.o, etc. I
can't find these in 2.4.0. Where have they gone? Without important
modules such as ip_masq_ftp.o I cannot use non-passive ftp from behind
the masquerading firewall.
# lsmod
Module
Size Used by
<snip>
iptable_filter
1824 0 (autoclean) (unused)
ip_nat_ftp
3280 0 (unused)
iptable_nat
13120 1 [ip_nat_ftp]
ip_conntrack_ftp
2016 0 (unused)
ip_conntrack
13408 2 [ip_nat_ftp iptable_nat ip_conntrack_ftp]
ip_tables
10784 4 [iptable_filter iptable_nat]
<snip>