Another basic networking question.

[Tim]

Tim:
>> That depends on how you're using the modem/router.  If you're using it
>> just as a modem, it's the computer network interface that gets assigned
>> the internet address, and the computer does the authentication (if any).
>> If you're using it as a router, the router's WAN interface deals with
>> the ISP.
 

Simon Slater:
> This explains some of the inconsistencies that I've been seeing.  So
> I'll settle on using it just as a modem and the computer for connecting
> until I finish tweaking the rest of the setup.

If you have more than one computer, it's typically easier to let the
modem/router handle the connection to the ISP, and be the
interconnection point between all the PCs on the LAN.  But if you want
flexibility in firewall management, then using a PC lets you do anything
that you can figure out, whereas many modem/routers have a very limited
set of options.

And from the point of view of getting technical support from an ISP, if
you have troubles with the internet side of things, they're probably
more willing, and able, to help you with your modem/router than Linux.

> I'll try again now I understand a bit more.  To configure the Linksys
> AG300, which is physically connected to eth0, I point a browser to
> 192.168.1.1 (by default, but this can be changed) and configure whatever
> I need to.  When I use the computer to connect to the ISP via the same
> eth0 and the ISP assigns me (at the moment) 210.84.25.73.  Does this
> mean that I cannot configure the router because the ip's are now on
> different subnets?  Then again, if used just as a modem, no real
> configuration is needed?

Another "it depends" answer...  Your modem might still respond to
192.168.1.1, to let you configure it, even you set it to act just as a
modem (otherwise you'd have to hit the big reset button to reconfigure
it, or have some other interface to the modem - like a serial port).
There would still be some configuration options for it just to act as a
modem (telephony related, perhaps some user controls), though the data
side of things would be handled by the PC (ppp logon, etc.).

>> If the computer is directly connected, it has to do all the firewalling,
>> and sharing the internet with other computers.  If you have a router in
>> between, it handles all the networking, and you don't have to have any
>> particular computers on to use the network.
 
> I do want this computer to most of the work.

Then you probably do want to use the modem/router as just a modem.  But
that's not a hard and fast rule.

-- 
[tim at localhost ~]$ uname -r
2.6.27.19-78.2.30.fc9.i686

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