ISA SERVER using ISA Server 2004 Enterprise Edition as

My network

3 Subnet Cisco router ? modem (bridge connection) <----> modem (bridge connection) ? ISA server (1 subnet)

I have 2 office with A and B

Office A have 2 subnet from 192.168.2.X, 3.x
Office B have only one subnet 192.168.4.X

– The client on subnet 2.x& 3.x want access everything on subnet 4.x & 4.x client want to access on 2.x,3.x
without isa i am geting both network using isa not able to Communicate both nwetwork