dhcp using cat 3550 EMi

[abricha]

I have 3 catalyst 3550 in access layer. each catalyst is connecting through a fiber to the core catalyst 4507 using trunking. The servers are in separate VLAN than the users. how do I assing Ip address to each user in different vlan.

can I create vlan interface on the cat3550 and use Ip helper address command ?

Or should I put the servers in the same vlan as the users?

I would like to keep all the servers in one separate VLAN.

[vincent-n]

HI there

Keeping the servers separate from the users is the right thing to do. Try the following:

1. Work out a plan of how many VLANs you want to have. You might want to have one VLAN per department in your office.

2. Make sure that you have a router (at least one) in your network that's capable of doing VLAN routing. This router can be a routing module on the 4507 or on the 3550 EMI. Trunk all the links that inter-connect the switches.

3. Create sub-interfaces on the router(s) and also create VLANs on the switches.

4. Setup a DHCP server on your network (you should already have one). Setup DHCP scopes on this DHCP server for each VLAN.

5. Assign the command "ip helper-address" on each of the sub-interface that points to the DHCP server.

That should be all that you have to do. You might want to do some reading prior to carry out the stuff I mentioned above. Just go to cisco web site and search for VLAN Routing. Also consult your IOS Configuration Guide Book (specific to your version of IOS of course).

Good luck

[abricha]

1. I have 4 cat 3550, each 3550 for each department.

2. why do I need a router if the cat3550 and cat4507 are capable of routing between vlans ? I am using trunking between 4507 and each 3550.

3. can I create 4 sub-interfaces or vlan interfaces on the 4507, each sub-interface for each department VLAN. and assign ip helper-address to each vlan interface.

can I still assing ip address for different Vlans from one dhcp server ?

The dhcp server is in separate vlan

thank you for your response