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New Member

3 VLANS each with a different network address

Is it possible to segment a managed switch into 3 seperate vlans that each have a different network address or do vlans have to have the same network address? Would this require 3 interfaces on the router for the switch to connected to?

5 REPLIES
New Member

Re: 3 VLANS each with a different network address

Yes. It is possible to configure a switch with 3 separate vlans each with different network addresses.

Yes, it would require 3 separate interfaces or a trunked interface on a router for devices on each vlan to see each other.

Each vlan should have its own network address if devices from one vlan need to see devices from another.

Mick.

New Member

Re: 3 VLANS each with a different network address

Thanks John!

Here is another question: can I get away with having no vlans and just a link from a router to the switch with the 3 seperate networks?

New Member

Re: 3 VLANS each with a different network address

Yes, but the devices on each network won't see each other exactly... they'll see each other's broadcasts though. That could get confusing for some devices.

You can put secondary addresses on the router (2... 1 for each additional network) to support the other two "networks'" default gateway addresses.

Mick.

New Member

Re: 3 VLANS each with a different network address

Thanks again Mick!

O.K. Last quiz question! My setup is going to have a router, firewall device, and a switch. Between the switch and firewall will be two links (two networks). Between the firewall and router will be one link. If I manage the switch so that it is 2 VLANs, one for each network, will that be difficult to implement? The switch is 3com, so would I just implement 802.1q and make the link from firewall to router a trunk link? Any advice would be appreciated!

New Member

Re: 3 VLANS each with a different network address

I don't know enough about your hardware to answer this question well.

You *can* trunk from your switch to your firewall on the private interface *if* both your switch and firewall support the same trunking protocol (802.1q).

I'm assuming your config looks something like:

internet-router-link1-firewall-trunk-switch

If link1 is a crossover cable or a separate switch/hub, this would work fine except the two VLANs won't be able to see each other since the firewall probably won't route packets back inside from inside.

Mick.

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