I think I found something. While testing the suggested trick by ussing mod ip_conntrack I found that it is loaded AFTER ip_tables for the HN - a excerpt from dmesg follows:
Nov 1 16:40:24 master kernel: ip_tables: (C) 2000-2002 Netfilter core team
Nov 1 16:40:24 master kernel: NET: Unregistered protocol family 17
Nov 1 16:40:24 master kernel: NET: Registered protocol family 17
Nov 1 16:40:24 master kernel: ip_conntrack : parameter ip_conntrack_enable_ve0 is obsolet
ed. In kernel >= 2.6.15 connection tracking on hardware node is enabled by default, use ip
_conntrack_disable_ve0=1 parameter to disable.
Nov 1 16:40:24 master kernel: ip_conntrack version 2.1 (4095 buckets, 32760 max) - 328 by
tes per conntrack
I just placed the options line at the beginning of /etc/modprobe.conf, what should I do yo load it before ip_tables?
Thank you.