Firewall Client local addresses
By default, a Firewall Client considers addresses specified as local all addresses on the network for which it is configured, in addition to the addresses specified in the local routing table on the Firewall Client computer. For example, if the Firewall Client connects to the network adapter for the Internal network, then all IP addresses configured on the Internal network are considered local. Each time a Winsock application on that client attempts to establish a connection to an IP address, the Locallat.txt file is used to determine whether the IP address is on the internal network or is external. If the address is considered local, the connection is made directly. If the address is not considered local, the connection is made through the Firewall service on ISA Server.
A local version of this information can be created, as well. Using a text editor, create a custom client LAT file named Locallat.txt and place it in the \Documents and Settings\All Users\Local Settings\Application Data\Microsoft\Firewall Client 2004 folder on the Firewall Client computer. You can add additional IP address ranges that the client recognizes as part of the local network. The client uses its own routing table, the server-specific settings, and Locallat.txt file to determine which IP addresses are part of the local network.
When you create the Locallat.txt file, enter IP address pairs in the file. Each address pair defines either a range of IP addresses or a single IP address. The following example shows a Locallat.txt file that has two entries. The first entry is an IP address range and the second entry is a single IP address. Note that the second entry is an IP address and not a subnet mask.
10.51.0.0 10.51.255.255 10.52.144.103 10.52.144.103
