Some questions on networking gateways

[Timothy Murphy]

Anoop wrote:

>> These questions arise because I tried changing my server
>> to machine 192.168.1.5, connected to the modem.
>> Everything worked fine on the new server,
>> but I could not access the ethernet on other machines,
>> even after modifying the route tables on these machines
>> to have default gateway 192.168.2.5 (the new server).
>>
>> I tried both with NetworkManager and with the network service,
>> but neither worked satisfactorily.
>>
>> Any enlightenment gratefully received.

> To get Internet on your client machines, you need to enable IP
> forwarding on server (I am not sure whether its enabled by default or
> not) and then you need to add a SNAT rule with the IP address
> '192.168.1.254' (your server's WAN side IP)

Thanks for your advice.
However, I probably didn't explain my setup clearly enough,
as the settings on my new server are identical as far as I can see
to those on the old server.

My setup, in brief, is
Internet -> Boolean ADSL modem -> server -> LinkSys WiFi router .

I actually run shorewall, where I assume any SNAT rule would be added.
There is no mention of 192.168.1.254 in the shorewall rules,
or indeed anywhere in /etc/ on the old server (except in openvpn data).

I see it is given in /var/lib/dhclient/dhclient-eth0.leases
on the old server (and is given as default gateway by "route -n"),
but I don't know how it got there.

I should say the issue is somewhat academic for me now,
as I had to decide if I could install the new server
before leaving on a 2 month holiday.
In the end I was not able to do so,
and had to leave the slightly unhealthy old server in service.




-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland