Alain a écrit :
> Francois Labreque nous illumina en ce 2008-09-20 14:45 -->
>> Tom Austin a écrit :
>>> Orchid XP v8 wrote:
>>>>>> The Internet gateway is a Cisco router. I don't have the password 
>>>>>> - and frankly, if I did I wouldn't know what to do with it.
>>>>>
>>>>>
>>>>> How many physical connections from your internal network to your 
>>>>> internet gateway - the Cisco router?
>>>>
>>>> Just one.
>>>>
>>>
>>> Get an old hub and put on the line.
>>>
>>> then run a patch from hub to a computer running a packet sniffer
>>>
>>>
>>>
>>>
>>> current hookup
>>>
>>> SWITCH-----------------------CISCO ROUTER
>>>
>>>
>>> sniffer hookup
>>>
>>> SWITCH------------HUB------------CISCO ROUTER
>>>                    !
>>>                    !
>>>                  SNIFFER
>>>
>>>
>>>
>>
>> Be sure to put a cross-over cable between the hub and the switch!
>>
>> This being said, unless Andrew doesn't care about his job, I wouldn't 
>> recommend playing around with the network like that.
>>
>> Problem 1:  Both the switch and router are probably set to full 
>> duplex.    If the sniffer or hub sends packets, it may cause 
>> collisions that would look very suspicious on a full duplex link  (I'm 
>> assuming that one of the reasons to go to Cisco hardware 2 years ago 
>> was for remote management)
>>
>> Problem 2:  If they are serious about security, the switch will be 
>> configured to allow only one mac address (the router's) and any packet 
>> transmitted by the sniffer PC or hub would cause the port to alarm or 
>> shutdown.
>>
>> Problem 3: the unpluging of the router and connection to the hub might 
>> be enough to send an alert to the Powers-That-Be(tm).
>>
>> Chances are they already have network usage stats anyway.
>>
> Normaly, when you use a hub, switch or router, you don't need a 
> crossover cable. The crossover is done by the hub/switch/router. 
> Crossover cables are used to dirrectly connect 2 computer by an ethernet 
> cable.
> 

Cisco Catalyst switches - which is want Andrew said they were installing 
in his office a few years ago - do not do that as they expect whoever 
installs them to know what they are doing and cable the things through a 
cable-management plant where punching down straight-through or 
cross-over connections offers more flexibility.

Auto-MDI/MDIX hubs and switches are for home offices where people 
usually do not have extra cables lying around, or do not even know the 
difference.

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