>Very simply...
>
>
>WORKSTATION <--------------->|
> | HUB
> SERVER <--------------->|
>
>
>That's way I don't understand that they can't see each other anymore.
>
>
>>Ok using a hub & not a router kinda changes things...
>>
>>I don't quite understand you're configuration....
>>
>>You have how many machines connected to what?
It seems your computers are trying to get IP addresses dynamically, through DHCP. This seems unnecessary for such a simple setup.
Instead of automatically getting an IP address, try giving each machine a static IP address. It is preferable to use private addresses.
Thus, the server might have the address 10.0.0.1, and the workstation, 10.0.0.2 Subnet mask, in both cases, might be 255.255.255.0.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)