> >Do I have to spell it out every single time?
> I agree with John and Mark. You descriptions are somewhat difficult
> to decode. However, you finally described the problem clearly in the
> next paragraph.

Sorry, I guess I am just getting somewhat impatient after all the
problems I have been experiencing lately, the last one being my T42p's
mother board dying on me...

> >You are not answering my question. I have both of my ThinkPads
> >running, none of them being used for any internet traffic at all, yet
> >within a couple of minutes or so, they will both lose their connection
> >(see my definition of that above). Now, if I have one ThinkPad running
> >only, I can do whatever I want with my internet connection, no problem
> >things will be working just fine, but as soon as I start using my
> >other ThinkPad, then both ThinkPads will lose their connection (again,
> >see my definition of that expression above). So, what kind of non-
> >Internet related load could get my two ThinkPads to lose their
> >connection?
>
> Kinda sounds like a duplicated IP address. Let's do some diagnostics
> and see what happens. On *BOTH* laptops, run:
> Start -> run -> cmd <enter>
> ipconfig /all | find "Address"
> You should get something like:
> C:> ipconfig /all | find "Address"
> Physical Address. . . . . . . . . : 00-02-B3-1E-43-17
> IP Address. . . . . . . . . . . . : 192.168.1.11
> Both lines should be different on the two laptops.

Agreed and they are/were.

> If the Physical Address (MAC address) is the same, the two computers
> were setup by cloning and have the same MAC address in the registry.
> That won't work, but is also improbable as the T42p and X41 laptops
> are quite different. Worth checking anyway as there are some
> utilities that do the same thing.

I did, at some point, check their respective MAC address as I entered
them so that the DHCP server could assign the ThinkPads a unique IP
address.

> If the MAC addresses are different, but the IP Address is the same,
> then you have a static IP address setup on one or both machines which
> will need to either change, or be converted to a more usable DHCP
> assigned IP address.

I went through all of that and, as far as I can tell/remember,
everything was 'fine', yet...

> That fact that a 3rd laptop works just fine (probably because it is
> properly configured)

I have configured all three laptops myself and in the exact same way
(as far as I can recall).

> leads me to suspect that the problem is in the
> DSL-G624T and not in the laptops. Any chance you have more MAC
> addresses configured in the filter than you have DHCP assigned IP
> addresses available in the IP address pool?

How do you mean? I am not at home right now, but I believe to have
plenty of IP addresses (192.168.1.2 to 192.168.1.255, if I recall
correctly), while I can only set an IP address to 5 or 6 MAC
addresses.

> Are you using a RADIUS server for authentication? Probably not as
> you're using MAC filtering which is largely a waste of effort.
> However, if you are using a RADIUS server, any chance that it has some
> manner of authentication user limit?

I have heard of that kind of server, but I must confess that I have no
idea as what its purpose is. What is it? How do I find out whether I
use one or not?

> It's also possible that the router is configured to only allow a
> limited number of wireless connections, or some other form of
> misconfigured security.

Not sure about that, since I can use two laptops (as long as they are
not my two ThinkPads).

> Can you plug the two laptops into the network using ethernet CAT5
> cables instead of wireless? If so, do they co-exist?

I haven't tried that, but I should have indeed tried it. Will do so as
soon as I get my T42p back. Thanks for the suggestion!

> There are some other obscure misconfigurations and combinations
> possible, but let's check the easy stuff first.

I am sure it will turn out to be something trivial (as usual). Just a
bit of a pain at the moment, as I have got the feeling that I have
tried everything (well, not quite, since I didn't try both ThinkPads
connected to the router via a cable for instance).

Alan.