VPN connect can't get the IP in the same subnet like internal network with 192.168.1.x
I set up a ISA 2006 firewall and created a VPN connection set up for testing. In the first step of "configure address assignemnt method"; in the first tag-"Access Networks' I chose "External"; in the second tag "Address Assignment", when i chose DNCP, i couldn't get VPN dial up connection successfully, so i decided to use "Static Address pool";when i tried to add IP address range, if i define start and end address under 192.168.1.X subnet, it says Networks cannot contain IP addresses that overlap with another network. I couldn not apply the change.
If i use another subnet like 192.168.2.X, i would successfully apply the change, however, after my client dialled up using VPN, it can only get IP address in the subnet of 192.168.2.X. How can i set up my client to use the same subnet as internal subnet.
Tne even worse issue is, after i tried many time, i restart the ISA services, however, all my old firewall polies were lost except the VPN one. Did anybody meet this stange phenomenon? My boss asked me to get the result before i deploy it on production environment.
Any guru here is willing to help me with this? I will appreciate your any instructions.