Overlapped Vlan ports

[Tato1]

My name is Marcos I have six servers connected each one to a 3com 3824 switch port that should be accessed from five diferent buildings conected to ports on the same switch , at this moment theres only the default VLAN configured, so everybody sees everybody, and there´s a big broadcast domain and I´d like to segment this. I want that every building will be able to see all the servers but not each other.So each VLAN has to have a port that goes to a building and all the server´s ports (Overlapped portbecause they will belong to more than one VLAN)
I really could not make it work and I will really appreciate your help. Thanks.Marcos

 

[techr]

There are 2 types (generaly) of VLAN ports. Untagged and tagged ones. When you plase a given switch port to untaged VLAN the switch will remove the VLAN ID tag for outgoing frames trough this port. The reason - compitability with non VLAN aware devices (most of the low cost NICs and switches.
The tagged ports means that the switch won't remove the VLAN ID tagg from outgoing frames. Using this taggs the remoute switch will place the frames to the appropriate VLANs configured locally.
You can definy one switch port as a tagged member of manny VLANs and as a untagged member in only one VLAN.
In your case you should configure the server ports as a tagged members of everey configured VLAN. Pay attention that the server's NIC must support multiply tagged VLANs too (3C996B-T/SX or any Intel Express PRO for example).
When you configure a new VLAN in your server, the operational system will see only the created virtual addapter, i.e OS will see VLANs as separated NICs. You must configure different IP networks for each VLAN in you network. Sometimes it is better to bay a Layer 3 switch and route between server VLAN and other VLANs to avoid preconfiguring the IP networks in your network.