[Openswan Users] iptables problem

Vernon A. Fort vfort at provident-solutions.com
Thu Dec 2 09:24:35 CET 2004


I have a VPN running:  Fedora Core 3 using iptables and openswan ipsec

    192.168.1.0/24   => GW1 (FC3) <=INTERNET=> GW2 (FC3) <=> 192.168.2.0/24

I know the VPN is working - I can drop the firewall and ALL traffic is 
passing both ways.

Side note - with FreeSwan, I was use to seeing the ipsec0 interface but 
now it appears that everything goes out the nornal public interface - 
why the change? - this made it very easy to add filtering.

With the firewall active - oddly enough I can ping either side but 
that's it.  I attempt to Remote Desktop from one NT server to the other 
and nothing, not RDP, FTP, etc... but ping will work.  I use a firewall 
script called gShield and have modified as followed:

        $IPTABLES -A INPUT  -p udp --sport 500 --dport 500 -j ACCEPT
        $IPTABLES -A OUTPUT -p udp --sport 500 --dport 500 -j ACCEPT
        $IPTABLES -A INPUT -p ESP -j ACCEPT
        $IPTABLES -A OUTPUT -p ESP -j ACCEPT
        $IPTABLES -A INPUT -p AH -j ACCEPT
        $IPTABLES -A OUTPUT -p AH -j ACCEPT

Absolutely NOTHING will pass with just these rules in place.  But when I 
add on the 192.168.1.0/24 side:

    $IPTABLES -t mangle -A PREROUTING -i eth1 -p esp -j MARK --set-mark 1
    $IPTABLES -A FORWARD -i eth1 -m mark --mark 1 -d 192.168.2.0/24 -j 
ACCEPT

I can ping but nothing else.  Does anyone have a iptables example? or 
can anyone point me in the right direction.

Vernon


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