I need to provide a solutions as follwoing.
ISP link----->Rtr------>Firewall(Natting)------>Switch (for some 25-30 subnets).
Would like to know what type of switch I should use(L2/L3)?
I don't know how to route the traffic from switch to internal Natted interface of my firewall(say 192.168.0.1)?
How should I configure my VLAN(would like to know about some document over the same)?