I am reasonably new to linux and I am struggling…

I just installed Redhat 7.2..went through a painful experience of configuring the speedtouch usb modem to work on the BT adsl offering…so far so good…

Now I am trying to get my box to nat…I read the NAT faq…seems straight forward…

I can ping my inside interface and even my ppp interface…but that’s it…

Does anyone have any ideas…I would really appreciate any help….

You can execute this on the box that has the modem (server). I have read that this is not the best way to do it, but it will enable you to connect in the meantime. just change the xxx.xxx.xxx.xxx to the internal IP of the machine to be masq'd (or the client) You can use this to masq several machines too, just duplicate the command changing the IP.
'ipchains -A forward -i ppp0 -s xxx.xxx.xxx.xxx/0 -j MASQ'

The FAQ describes iptables not ipchains…and they are not compatible with each other….

This is what I ended up with now....

iptables is the new version of ipchains, thats all. ipchains works for me just fine. Just use ipchains for now and you can investigate the use of iptables at your leisure The command listed above will happily masq any traffic going out to the internet from the IP address you specify. This works fine on my setup, I have a linux server that the alcatel adsl modem is connected to, and I dual boot the client machine with windoze and linux both of which can access the inet throught the server.

Here is how I did it using iptables on an ethernet setup:

# internal
LAN_IP="192.168.168.1"
LAN_IFACE="eth0"
LAN_SUB="192.168.168/24"

INET_IFACE1="eth1"
INET_IP1=`ifconfig $INET_IFACE1 | grep "inet addr:" | \awk -F: {'print $2'} | cut -d\ -f 1`

iptables -t nat -A POSTROUTING -o eth1 -j SNAT --to-source $INET_IP1

echo 1 > /proc/sys/net/ipv4/ip_forward

# full access to eth0 nic
iptables -A INPUT -p ALL -i eth0 -s $LAN_SUB -j ACCEPT
iptables -A OUTPUT -p ALL -s $LAN_SUB -j ACCEPT
iptables -A FORWARD -i eth0 -d 0/0 -p all -j ACCEPT
iptables -t nat -A POSTROUTING -p all -d 0/0 -s 0/0 -j SNAT --to-source $INET_IP1

That is the basic setup. The rest of the script is the firewall setup. YOu will have to mod it some to make it work with your connection.

You will need to change the LAN addresses to match your machines, and it looks like bbenz3 is connecting with PPPoE, we connect with PPPoA so change eth1 to ppp0.