[ubuntu-uk] Shorewall internet sharing problems

[Tony Arnold]

Michael,

Michael Rimicans wrote:
> Greetings.
> 
>  Can any one show me the error of my ways with the following:
> 
>  Have set up shorewall on a gateway system to provide security and net 
> sharing duties.
>  After banging my head against a wall it has finally allowed me to 
> connect a networked computer through to the wifi router.
> 
>  Now heres where the problem lies.
> 
>  I'm able to connect to the router (192.168 blah blah) with no problems 
> but when I try to surf elsewhere nothing
>  happens.
> 
>  I'm able to ping the isp's dns server and get a reply and have tried 
> placing the address in the resolv.conf file on the gateway with no joy.

If you can ping from the client through the gateway and your router and
get a reply back, then basic routing seems to be working.

Your comment above implies it may be a DNS problem. If you type

  host www.ubuntu.com

in a terminal window, do you get a sensible response?

Is the client getting its IP address and DNS information via DHCP from
the gateway? What has it provided for the address of the DNS server? If
it's the gateway, then you should check the gateway is configured to act
as a DNS proxy, or you could set the DNS address manually in the client
(edit resolv.conf) to the address of the ISP's DNS and see if that helps.

Just some things I would look at.

Regards,
Tony.
-- 
Tony Arnold, IT Security Coordinator, University of Manchester,
IT Services Division, Kilburn Building, Oxford Road, Manchester M13 9PL.
T: +44 (0)161 275 6093, F: +44 (0)870 136 1004, M: +44 (0)773 330 0039
E: tony.arnold at manchester.ac.uk, H: http://www.man.ac.uk/Tony.Arnold