Ip_forward allows packets to go from one interface to another - without netfilter. So your setup should allow all packets - it should be acting just like a router -----Original Message----- From: netfilter-admin@xxxxxxxxxxxxxxxxxxx [mailto:netfilter-admin@xxxxxxxxxxxxxxxxxxx] On Behalf Of Minh Cao Sent: Thursday, January 15, 2004 2:57 PM To: netfilter@xxxxxxxxxxxxxxxxxxx Subject: Re: Help: Iptables rules > Some questions: > > 1. Do you have packet forwarding turned on in the kernel (cat > /proc/sys/net/ipv4/ip_forward)? Yes, I have ip_forward > > 2. What are the default policies on your netfilter chains (iptables -L)? Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy DROP) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere LOG all -- anywhere anywhere LOG level warning Chain OUTPUT (policy ACCEPT) target prot opt source destination > > 3. You say the above has not worked - how have you tested it? Yes, I tested I used VPN client, which connected to remote side. After connected, the password authentication is timeout in 2 minutes. Here is my network diagram Internet --> CheckPoint Firewall --> (linux/NAT/IPtables/DHCP with 2 NICs) --> DHCP/VPN client To verify the packets at Checkpoint firewall, I connect VPN-client before IPtables hosts (right after the Checkpoint firewall) , the VPN client connected and password auth. w/o a problem. > > 4. Do packets get across the router in either direction (internal to > external? > external to internal)? How do I check this ? Telnet, ftp, ping all working > > 5. Have you read Oskar Andreasson's netfilter tutorial at > http://iptables-tutorial.frozentux.net, referenced on the netfilter home > page > http://www.netfilter.org/documentation/index.html#documentation-tutorials? I will read > > 6. Did the machine work as a simple router before you tried adding > netfilter > rules? Two NICs are on different subnet. Can I config as a router w/o using netfilter ? > > Regards, > > Antony. -- The difference between theory and practice is that in theory there is no difference, whereas in practice there is. Please reply to the list; please don't CC me.
