Need help with ip forwarding

[bhavink]

Hello,

I have a linux machine which is connected to the other linux machine through ethernet over usb. Both the linux machines are running ubuntu. The second linux machine is connected to wifi router and wifi router is connected to windows systems over wifi. Lemme just put it like this,

linux machine 1<---usb--->linux machine 2<---wifi-->router<---wifi--->windows

linux machine 1 usb0 : 172.20.1.103
linux machine 2 usb0 : 172.20.1.1
linux machine 2 wlan0 : 192.168.2.2
wifi router : 192.168.2.1
windows system : 192.168.2.91


Now, i want to ping windows from linux machine 1.
i am able to ping wlan interface of linux machine 2 as well but after that i am not able to ping router nor windows.

1. i made echo 1 > /etc/sys/net/ipv4/ip_forward
2. I even tried all sort of iptables rules.


Any help would be appreciated.

Thanks,
Bhavin

[Lazydog]

IP addresses and routing tables for all devices would be nice to see where the problem might be.

[bhavink]

Hi,

Following the route table on linux machine 1,

bhavin@ubuntu_machine1:~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
* 172.20.1.1 255.255.255.255 UH 0 0 0 usb0
default * 0.0.0.0 U 0 0 0 usb0


following is the route table on linux machine 2,

bhavin@ubuntu_machine2:~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 * 255.255.255.0 UH 0 0 0 tiwlan0
172.20.1.0 * 255.255.255.0 U 0 0 0 usb0

[bhavink]

Anyone can help me out plz. I am kind of stuck with this issue.

[Lazydog]

what does traceroute show from host 1 to the windows server?