Difference between revisions of "NAT Gateway by iptables dnsmasq"

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sysctl -w net.ipv4.conf.default.forwarding=1
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sysctl -w net.ipv4.conf.default.forwarding=1 net.ipv4.conf.all.forwarding=1
sysctl -w net.ipv4.conf.all.forwarding=1
 
 
iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE
 
iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE
 
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 3074 -j DNAT --to-destination 192.168.0.203
 
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 3074 -j DNAT --to-destination 192.168.0.203

Revision as of 00:44, 5 January 2011

The following guide can be followed on the palm to make a NAT gateway from a usb0 (tether) to ppp0 (EVDO). It is also possible this can be adapted to use a palm pre as a usb wireless adapter, that is NAT gateway from usb0 to eth0. Since wpa_supplicant and wireless tools are included with webos it is also possible that these could be adapted to build your own wifi hotspot from built in commands.

https://help.ubuntu.com/community/Internet/ConnectionSharing

Turn on USBnet on palm

get a root terminal and enter the commands: This requires a reboot so exit anything you're doing on your phone.

usbnet enable
reboot

Make dnsmasq.palm.conf check our config file (only do once)

mount -o remount,rw /
echo conf-file=/etc/dnsmasq.usb.conf >> /etc/dnsmasq.palm.conf
mount -o remount,ro /

Make dhcp/dns availalbe to usb0

get root terminal and use the following to make dhcp/dns available to usb0

mount -o remount,rw /
echo interface=usb0 >> /etc/dnsmasq.usb.conf
echo dhcp-host=192.169.0.202 >> /etc/dnsmasq.usb.conf
echo dhcp-range=192.168.0.203,192.168.0.203,15m >> /etc/dnsmasq.usb.conf
stop dnsmasq
start dnsmasq
mount -o remount,ro /

Make Sure usb is correct address

Attach the usb cable between your computer and palm.

Run

ifconfig usb0

on your palm and make sure the IP is 192.168.0.202

ifconfig usb0 up
ifconfig usb0 192.168.0.202

Technically, you don't need this address but it sure makes it easier if you are using ssh to get your root terminal as this appears to be the default usb address :/

A note on SSH root terminal

novaterm users skip this step.

You'll want to connect to the root terminal from here on out using usbnet. So open your computers connection to the usbnet.

Saving your initial iptables settings (optional)

iptables is reset every time your palm is rebooted. But if you wish to save your iptables settings to avoid a reboot here is how.

iptables-save -c > /media/internal/iptables.save

Setup packet forwarding to tether usb0 (cable) to ppp0 (EVDO)

You will need to shut off wifi on your phone (it won't work otherwise). To do this tap on the upper left hand corner where the wifi icon is. Select "Wi-Fi" -> Turn off Wi-Fi

sysctl -w net.ipv4.conf.default.forwarding=1 net.ipv4.conf.all.forwarding=1
iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/24 -j MASQUERADE
iptables -t nat -A PREROUTING -i ppp0 -p tcp --dport 3074 -j DNAT --to-destination 192.168.0.203
iptables -t nat -A PREROUTING -i ppp0 -p udp -m multiport --dports 88,3074 -j DNAT --to-destination 192.168.0.203
iptables -A FORWARD -i ppp0 -d 192.168.0.203 -p tcp --dport 3074 -j ACCEPT
iptables -A FORWARD -i ppp0 -d 192.168.0.203 -p udp -m multiport --dports 88,3074 -j ACCEPT

Setup packet forwarding to tether usb0 (cable) to eth0 (Wi-Fi)

Make sure your Wi-Fi is on and connected to an Access Point.

sysctl -w net.ipv4.conf.default.forwarding=1 net.ipv4.conf.all.forwarding=1
iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 3074 -j DNAT --to-destination 192.168.0.203
iptables -t nat -A PREROUTING -i eth0 -p udp -m multiport --dports 88,3074 -j DNAT --to-destination 192.168.0.203
iptables -A FORWARD -i eth0 -d 192.168.0.203 -p tcp --dport 3074 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.203 -p udp -m multiport --dports 88,3074 -j ACCEPT

Setup your computer

It may help to disconnect other network interfaces at this point on your computer (through network manager). If you used SSH to connect to your phone you need to disconnect the usb network connection (in the network manager not the cable).

On Ubuntu Linux 10.04 in network manager right click the icon select "Edit Connections". Find the wired interface probably named "Auto usb" edit and uncheck "connect automatically" box.

Windows / Mac instructions coming soon.

Restoring your palm to it's original settings

sysctl -w net.ipv4.conf.default.forwarding=0 net.ipv4.conf.all.forwarding=0
mount -o remount,rw /
echo -n "" > /etc/dnsmasq.usb.conf
stop dnsmasq
start dnsmasq
mount -o remount,ro /

Restoring iptables (optional)

iptables-restore -c /media/internal/iptables.save 

Trouble Shooting

Make sure both these values are 1.

sysctl net.ipv4.conf.default.forwarding net.ipv4.conf.all.forwarding

Beware, the palms seems to like setting this to 0 whenever network settings are changed.

References