Dear Sir

thank you a lot for your reply.

i want to derive benefit from your experience regarding splitting the outside and inside interfaces to sub interfaces.

i have two outside routers for internet connections have to e connected to the firewall, so i want to divide the inside and outside interfaces to two sub interfaces; because each outside router has differnet internal IP addresses .

but the question is that in transparent mode, each interface has to get different VLAN "does this mean that i have to give the interface a tag" so how can i access the routers from the inside; by this it will be different network ( the inside and the outside considered as different networks).

Thanks

even though you configure different vlan-tag's on the inside & outside interfaces ( both the vlans share the same ip-address space ), that way having your gateway ip-address residing on the outside interface and hosts connected to the inside interface will help you in filtering the traffic as it passes through the firewall

check this example

http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a008089f467.shtml

even though the above example doesn't talk about context's it will help you understand the network design while implementing transparent firewall.

HTH

Vikram