[lug] Networking and security help

[Kirk Ellsworth]

I have a client that is install high speed internet into a few building and
leasing the units out.  I am putting a Cisco firewall into the leasing
office, and using a managed Cisco switch as well.

There will be a large amount of units and security from unit to unit is a
concern of mine.  Does anyone have a suggestion on the best way to do this?
Do I add a DHCP server to the leasing office or do I let the router assign
IPs?  What do I need to consider if I only want the units to reach the WAN
via the T1 router and not have any access what so ever to other units?

Also if I have 10 buildings with leased units in each what would be the best
way to subnet these buildings.

Anything will help here.

Thanks in advance

ke