Hi Thomas! Thank you for your response again. The default gateway of FE is the IP address of NetscreenFW2 >> 10.10.4.253. The network between ISA and NetscreenFW_2 is transparent. The network that represents the internal network on ISA is: from 10.10.4.0 to 10.10.4.255 and from 10.255.255.255 to 10.255.255.255 Best Regards Mustafa