T1 or LAN connections require two Network Interface Cards (NICs) installed in the WinRoute computer. One NIC will link to the Internet (e.g. router) while another NIC will link to the internal network.
To connect to the Internet:
Go to menu Settings->Interface Table
Choose NIC linking to the Internet, click on Properties and check ON "Perform NAT with IP address of the interface on all communication passing through". When opening the interface table dialog box you will see NAT ON beside this external line.
Check than NAT is NOT ON for the Interface linking to the internal network (go to the properties of this interface in the Interface Table)
Check that there is NO gateway set in TCP/IP properties of the internal NIC (go to network settings) and NIC has assigned an internal IP address.
Check that NIC linking to the Internet was properly assigned with data from your ISP. In case you have a dynamically assigned IP addresses leave the IP address settings blank.