[RndTbl] using hub to connect to shaw

[Dan Martin]

On 20-Dec-08, at 12:43 PM, Mike Pfaiffer wrote:

> Dan Martin wrote:
>> This should be simple, but for some reason I can't get it working.
>
> 	Should work. I did it before.
>
>> My present setup:
>> shaw cable modem ----> linux box / iptables ----> airport extreme  
>> ---->
>> a happy group of Mac & PCs, some wired, some wireless
>
> 	Essentially your Linux box is a router.
>
>> Problem:
>> My broker supplies me with software for streaming quotes that must  
>> run
>> on XP and not be behind a firewall.
>>
>> Solution (I thought):
>> Use my old Allied Telesyn CentreCOM MR815T hub/repeater, and take
>> advantage of the fact that Shaw will issue 2 IPs.
>> shaw cable modem ----> hub
>>                           port 1 |---------> linux box / iptables  
>> ---->
>> etc, as before
>>                           port 2 |---------> promiscuous XP box
>>
>> If I connect either the network (my present system) or the XP box
>> directly to the cable modem, each seems to work.  If I connect  
>> either of
>> these through the hub, it no longer works.  A diode will light up
>> showing the connection of a PC to a particular port, but will not  
>> light
>> up when I plug in the ethernet cable from the cable modem.  The hub  
>> will
>> indicate activity when an attempt is made to access the internet,  
>> but no
>> activity is registered on the cable modem.
>
> 	Ah I think I see your problem. You touch on it later.
>
>> I have used different ports on the hub, 3 different ethernet cables  
>> to
>> connect the modem to the hub, and at times I have rebooted the  
>> modem or
>> the PC attached to the hub (various permutations of these actions).
>>
>> The hub has 8 ports - the first 7 are labelled with an "X" which I
>> believe means MDI-X (crossover) configuration to plug a PC into.   
>> Port 8
>> has a switch to select MDI or MDI-X.  What should I plug the modem  
>> into?
>> (I have tried both).
>
> 	You use regular (not crossover) cables in the first seven.

To the best of my knowledge, none of my cables are crossover.

> Port 8 can
> use either depending on the position of the switch. Your machines  
> should
> connect to any of the first seven ports. The cable modem connects to
> port 8.
I assume the switch is set to "MDI" (unlike the "MDI-X" of the other  
ports, since the modem seems to behave like an "un-PC" in its  
connectivity - though the computer store guy said to use one of the  
regular ports).
I don't know if this "uplink" port has any other special features  
other than the ability to select "MDI" vs "MDI-X".  Does the hub  
expect traffic from this port to be directed to the other ports?  I  
don't know if this hub has switching capabilities, but I expected that  
each port was equivalent to the others.

> The other potential problem I can see at this point might be a
> break in a cable...
I tried 3 different cables - one of which I tested and appears to work  
when used to connect the modem to computer directly.

>
>
> 				Later
> 				Mike
>
>
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Dan Martin
GP Hospital Practitioner
Computer Scientist
ummar143 at shaw.ca
(204) 831-1746
answering machine always on