what IPTABLES to add to arno-iptables-firewall to allow IPSEC?

[hanasaki]

I have a Linksys RV042 inside the firewall wall (iptables with arno) and need to add the right rules to the linux firewall to let the linksys create its tunnel to another site with another linksys box. What rules need to be added?

Thanks,

[stlsaint]

see HERE (https://help.ubuntu.com/community/IptablesHowTo).