routing with NAT

sunlinux · 06-30-2008, 04:47 AM

Setup:
1.
------192.-168.123.5---eth0(LAN)----linux with NAT---eth1(internet)

2. A wirelss router is connected to our VPN server

------LAN Port ip192.168.123.7 (wireless router)----Port WAN--- VPN ip server .

I want to connect that vpn network thru my linux server above.

client machin: 192.168.123.4 gw 192.168.123.5

I have added route in linux server:

network: 192.168.10.* gw 192.168.123.7

but I could not access vpn ips.

Pls. help

estabroo · 06-30-2008, 10:07 AM

Did you turn on ip forwarding? cat /proc/sys/net/ipv4/ip_forward; If its a 0 your aren't forwarding through your box. You can turn it on temporarily by doing echo 1 > /proc/sys/net/ipv4/ip_forward

You can turn it on permanently usually by adding a line to your /etc/sysctl.conf (something like net.ipv4.ip_forward=1 or net/ipv4/ip_forward=1). Most distos have good examples and possibly even a forward option already in there that just needs to be uncommented.

sunlinux · 06-30-2008, 11:45 PM

Hi it's enabled already..but not working

estabroo · 07-01-2008, 06:16 PM

The next thing to check is where the vpn ips are sending 192.168.123.0/24 traffic. I'd bet they are sending it out their default route and that their default route is not the same box that has the 192.168.123.7 ip.

192.168.123.4 -> 192.168.123.5 -> 192.168.123.7 -> (some vpn ip) -> ????

The packets are getting there, they just aren't coming back is what I'm guessing.