I think you probably know all this but I'm posting it here anyway
OK, lets check some stuff... go to your linux server and connect the ADSL to the internet. Now open a shell and type the following...
Check the inet addr for eth0 and ppp0 and write them down.
You should get somthing like this...
owen@loki:~ > dig
; <<>> DiG 8.3 <<>>
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0,
h27m5s IN A 126.96.36.199
;; Total query time: 53 msec
;; FROM: loki to SERVER: default -- 188.8.131.52
;; WHEN: Mon May 13 20:50:24 2002 **^^^^^^^^^^^^^^**
;; MSG SIZE sent: 17 rcvd: 436
The bit you want is the IP address up there above the **^^^^** bit. Thats your ISPs DNS for you.
then get the DNS hostname by typing...
nslookup <add the DNS IP here>
and you get...
owen@loki:~ > nslookup 184.108.40.206
write this stuff down and head over to your windows machine with your bit of paper.
Now make sure that the config in the windows networking setup matches everything here...
The DNS hostname is imsdns07 and the domain is ims.bt.net
The gateway is the inet addr from eth0 (192.168.0.1)
also make sure the IP's on both machines are in the same subnet (192.168.0.xxx) but if you can ping then this is OK.
Now, go back to the server and make sure it's still connected to the internet. You need to do the next bit as root so go to the shell and type the next lines...
(enter your root password)
ipchains -A forward -i ppp0 -s 192.168.0.2/0 -j MASQ
You should now be able to ping the inet addr of ppp0 that you wrote down earlier. if you can then linux is doing it's masurading for you. you should also be able to ping names such as anduin.net too, if you can then the DNS is working for you too.
If it doesn't, then I would say that there is a firewall problem. Disable _all_ the firewall and masqurading stuff that you have setup (you need to remember it _all_)and try again.