[SOLVED] Internet Gateway

Hi guys, Can someone let me know where I'm going wrong!??

I'm trying to set up an Internet Gateway by following the examples on here and at: https://help.ubuntu.com/community/Internet/ConnectionSharing

This is my set up:

Internet <<==>> eth1 (192.168.1.50)<> Ubuntu gateway <> eth0 (192.168.0.210)<<==>> Client PC

The client PC has the following static setup IP: 192.168.0.78 Subnet Mask: 255.255.0.0 Default Gateway: 192.168.0.210

I have followed the instructions to enable IP forwarding but I can't get passed the Gateway! The client PC can ping eth0 and the gateway can get out to the internet. Unfortunately the client PC can't access the internet so I must have made an error with the forwarding.

Can anyone help me, please? :D

The error is most likely in your iptables script. Post that please, i'll provide any help i can.

Hello s3gfault, First off apologies I'm a complete noob to Linux!

I used the command "sudo iptables -L" to list the rules shown below:

Chain INPUT (policy DROP) target prot opt source destination ACCEPT tcp -- 192.168.1.3 anywhere tcp flags:!FIN,SYN,RST,ACK/SYN ACCEPT udp -- 192.168.1.3 anywhere ACCEPT tcp -- 192.168.1.4 anywhere tcp flags:!FIN,SYN,RST,ACK/SYN ACCEPT udp -- 192.168.1.4 anywhere ACCEPT tcp -- 192.168.1.1 anywhere tcp flags:!FIN,SYN,RST,ACK/SYN ACCEPT udp -- 192.168.1.1 anywhere ACCEPT all -- anywhere anywhere ACCEPT icmp -- anywhere anywhere limit: avg 10/sec burst 5 DROP all -- anywhere 255.255.255.255 DROP all -- anywhere 192.168.1.255 DROP all -- 224.0.0.0/8 anywhere DROP all -- anywhere 224.0.0.0/8 DROP all -- 255.255.255.255 anywhere DROP all -- anywhere 0.0.0.0 DROP all -- anywhere anywhere state INVALID LSI all -f anywhere anywhere limit: avg 10/min burst 5 INBOUND all -- anywhere anywhere INBOUND all -- anywhere 192.168.0.210 INBOUND all -- anywhere 192.168.1.50 INBOUND all -- anywhere 192.168.0.255 LOG_FILTER all -- anywhere anywhere LOG all -- anywhere anywhere LOG level info prefix `Unknown Input'

Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT icmp -- anywhere anywhere limit: avg 10/sec burst 5 TCPMSS tcp -- anywhere anywhere tcp flags:SYN,RST/SYN TCPMSS clamp to PMTU OUTBOUND all -- anywhere anywhere ACCEPT tcp -- anywhere 192.168.0.0/24 state RELATED,ESTABLISHED ACCEPT udp -- anywhere 192.168.0.0/24 state RELATED,ESTABLISHED LOG_FILTER all -- anywhere anywhere LOG all -- anywhere anywhere LOG level info prefix `Unknown Forward'

Chain OUTPUT (policy DROP) target prot opt source destination ACCEPT tcp -- 192.168.1.50 192.168.1.3 tcp dpt:domain ACCEPT udp -- 192.168.1.50 192.168.1.3 udp dpt:domain ACCEPT tcp -- 192.168.1.50 192.168.1.4 tcp dpt:domain ACCEPT udp -- 192.168.1.50 192.168.1.4 udp dpt:domain ACCEPT tcp -- 192.168.1.50 192.168.1.1 tcp dpt:domain ACCEPT udp -- 192.168.1.50 192.168.1.1 udp dpt:domain ACCEPT all -- anywhere anywhere DROP all -- 224.0.0.0/8 anywhere DROP all -- anywhere 224.0.0.0/8 DROP all -- 255.255.255.255 anywhere DROP all -- anywhere 0.0.0.0 DROP all -- anywhere anywhere state INVALID OUTBOUND all -- anywhere anywhere OUTBOUND all -- anywhere anywhere LOG_FILTER all -- anywhere anywhere LOG all -- anywhere anywhere LOG level info prefix `Unknown Output'

Chain INBOUND (4 references) target prot opt source destination ACCEPT tcp -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT udp -- anywhere anywhere state RELATED,ESTABLISHED LSI all -- anywhere anywhere

Chain LOG_FILTER (5 references) target prot opt source destination

Chain LSI (2 references) target prot opt source destination LOG_FILTER all -- anywhere anywhere LOG tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/SYN limit: avg 1/sec burst 5 LOG level info prefix Inbound ' DROP tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/SYN LOG tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/RST limit: avg 1/sec burst 5 LOG level info prefix Inbound ' DROP tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,ACK/RST LOG icmp -- anywhere anywhere icmp echo-request limit: avg 1/sec burst 5 LOG level info prefix Inbound ' DROP icmp -- anywhere anywhere icmp echo-request LOG all -- anywhere anywhere limit: avg 5/sec burst 5 LOG level info prefix Inbound ' DROP all -- anywhere anywhere

Chain LSO (0 references) target prot opt source destination LOG_FILTER all -- anywhere anywhere LOG all -- anywhere anywhere limit: avg 5/sec burst 5 LOG level info prefix `Outbound ' REJECT all -- anywhere anywhere reject-with icmp-port-unreachable

Chain OUTBOUND (3 references) target prot opt source destination ACCEPT icmp -- anywhere anywhere ACCEPT tcp -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT udp -- anywhere anywhere state RELATED,ESTABLISHED ACCEPT all -- anywhere anywhere

This seems like a huge amount of rules to me! Especially as for the moment I just want to let all traffic through. Any suggestions would be appreciated!?

well.. i think iptables may have been messed up.. Do this , flush your iptables http://prash-babu.blogspot.com/2008/10/how-to-flush-or-remove-all-iptables.html and then setup internet connection sharing by either using firestarter ( sudo apt-get install firestarter) or manually by this link http://ubuntuforums.org/showthread.php?t=91370

After a lot of fiddling and correcting a few stupid mistakes this is up and running. Thanks superprash2003 :KS