[SOLVED] Internet share between Ubuntu and Arch Linux

[carandraug]

Hi,

As the title says, I'm trying to share an internet connection between my Ubuntu and Arch Linux boxes. Ubuntu gets internet through wireless and I want it to share with Arch through Ethernet. I've done it previously with success (with other computers) but for some reason I can't get it done this time.

Ubuntu gets wireless internet through wlan0 (it's an USB adapter) and connects through eth0 with an Ethernet cable to another eth0 in Arch

Here's a diagram of what I mean

router ))) wireless (((wlan0-Ubuntu-eth0<---Ethernet--->eth0-Arch

What I've done:

1. I enabled (I think) packet forward in Ubuntu by uncommenting at /etc/sysctl.conf the line

   net.ipv4.conf.default.forwarding=1

2. I tried to reload the settings with sudo sysctl -p but I've rebooted it since then so that's probably not an issue.
   
3. Both computers have the same DNS. In the arch box I went to /etc/resolv.conf and entered the same values I have in Ubuntu.
   
4. I made a connection between both computers by entering, in Ubuntu ,

   sudo ifconfig eth0 192.168.0.1 netmask 255.255.255.0 up

5. In Arch I setted Ubuntu IP (192.168.0.1) as gateway and gave him 192.168.0.2 as his IP.
   
6. In Ubuntu I entered

   sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

   which, if I understand correctly what says in the man pages, will forward the packets from Arch to wlan0.

The result:

• Both computers can ping each other.
• Can't ping anything else in Arch Linux.
• I don't think the problem is in the Arch since it's connected to Ubuntu, probably something that I missed in Ubuntu.

Can someone see where I'm going wrong? Thanks in advance

[carandraug]

I mananged to solve my problem with the help from nDuff at #ubuntu

after a look at "iptables -L -v -t nat" and "iptables -L -v", he noticed the counts as zero which pointed to a problem with the gateway in the Arch Box. And so it was. In the Arch Linux I did use the correct IP as gateway but I forgot to remove the "! from the line

ROUTES=(!gateway)

The "!" HAS to go if you want it to work. Can't believe I missed it.