Segmenting a network

[Tor Hildrum]

First of all, this is the hardware:
1x HP Procurve 2650
3x HP Procurve 2626
1x HP Procurve 2124

The current setup has the switches daisy-chained by ethernet.

We are renting out part of our office, so this is a good time to clean things up a bit. I'm going to need 3 logical LANs with routing/ACLs between them.

The new setup will look like this:
Router - 2626 backbone - switches

Physically, the people renting offices will be connected to our 2650, which again will be connected to the 2626 backbone.

Our IP-nett from the router is a class C nett, and we have no control over that part. So, I have to partition a class C address space.

My thought where to create 3 VLANs, and give them the following subnets:
MyCompany_VLAN(2) - 10.0.0.0/25
Company2_VLAN(3) - 10.0.0.0/27
Company3_VLAN(4) - 10.0.0.0/28

In addition to the logical segmentation, I need to make sure MyCompany can access Company2. Company2 needs to access MyCompany. Company2 needs to access Company3. Company3 needs to access Company2. Company3 and MyCompany should have no access to each other.

Is this a sound plan? And how would I go about implementing it? Can the 2650 do IP-source/destination blocking? I would like this segmentation to happen on the edge 2650 switch, and not deeper in the network.

Also, can the 2650 do DHCP on a VLAN? Or do I need dedicated DHCP-servers on each VLAN?

Truth be told, I've read the documentation for my 2650, but couldn't find any info about it.

[vve]

It is a good idea to divide the C-class network into 3 separate networks, which must not overlap. You create the 3 VLANs on the 2650, which supports routing. Traffic to and from the rented out networks must then pass the 2650. The 2626 must also know how to reach the 3 customer networks, which are behind the 2650.

Unfortunately, the 2650 is not capable of ACLs. The cheapest one to support it is the 3400cl. Don't expect too much of it though, it is very limited in capability in this respect.

[Tor Hildrum]

Would it be possible to do it like this:

DEFAULT_VLAN: 10.0.0.0/30
- Router 10.0.0.250

VLAN 1: 10.0.0.0/25
VLAN 2: 10.0.0.0/27
VLAN 3: 10.0.0.0/28

I configure the following static routes:
VLAN 1:
ip route to 10.0.0.0/27
ip route to 10.0.0.250 (gw-router)

VLAN 2:
ip route to 10.0.0.0/28
ip route to 10.0.0.0/25
ip route to 10.0.0.250 (gw-router)

VLAN 3:
ip route to 10.0.0.0/27
ip route to 10.0.0.250 (gw-router)

Local routing is then turned of on the router, so that it only routes external traffic in or out.

How does that look?