AltaVista Tunnel Telecommuter Client

96 Tunnel server This is the domain name or IP address of the tunnel server on the Internet and the port for which tunnel traffic is handled default 3265. First firewall The first firewall is not typically used for single remote PCs, as the traffic is transparent until received by the remote firewall. This first firewall is typically the end users ISP, through which outbound tunnel traffic passes transparently. On the Extranet server acting as an outbound tunnel client, the first firewall parameter lists the address and port default 3265 of the local firewall between the LAN and the Internet. Second firewall This is the physical address and tunnel port for the private network being accessed. Ultimately, it is the first destination for tunnel traffic, and it is relayed from the tunnel port on the firewall to the tunnel port on the Extranet server for verification.

6.4 VPNs and AltaVista

AltaVistas flexibility allows an enterprise to accept several tunnel sessions to the virtual private LAN, either from a remote LAN or from remote single machine connections. The configurations here are each subtly different, because the Single Connection-to-LAN and LAN-to-LANLAN-to-WAN implementations of the AltaVista Tunnel are different. The LAN-to-LANLAN-to-WAN tunnel configurations are for an enterprise that requires two-way tunnel traffic between its two networks where an Extranet server is required on each end of the connection. This scenario is actually meant to replace traditional private leased line connections by using secure tunneling sessions over the Internet. The Single Connection-to- LAN scenario allows multiple end users to access the private network over the Internet, in a secure fashion, without being tied to a fixed IP address or a single access provider. In the following sections we show a sample configuration illustrating each scenario.

6.4.1 Implementing a LAN-to-LAN Tunnel

This configuration features a firewall on each side.

6.4.1.1 Sample configuration

In the LAN-to-LAN tunnel configuration shown in Figure 6-1 , LAN 1 is a corporate office connected to the Internet via a full T1 and protected with a firewall. There are four machines on the LAN: the AltaVista Extranet server, Finance, Human Resources, and Research Development. LAN 2 is a remote sales office running a second AltaVista Extranet server and three host machines. LAN 2 is connected to the Internet via 128Kbps ISDN and is protected by a firewall. This configuration is set up to illustrate the ability of the AltaVista Tunnel server to act as either an outbound or inbound tunnel router. In this example, LAN 1 is the inbound tunnel group and LAN 2 is the outbound tunnel group. 97 Figure 6-1. Two Enterprise LANs connected over an AltaVista Tunnel

6.4.1.2 Tunnel server configuration

Since LAN 1 is the inbound tunnel network, its configured to accept tunnel traffic from LAN 2. The tunnel connection is dedicated, meaning it begins automatically and stays up constantly. Routing table The inbound tunnel server routes all incoming tunnel traffic to its local network address range 1.195.6.. Its routing table is set up like this: • Subnet : 1.195.6. • Netmask : 255.255.255.0 • Description : Local Tunnel Clients Dynamic IP tables The tunnel server, in this case, assigns 1.196.5.1 to the tunnel pseudo-adapter on its end, and 1.196.5.2 to the pseudo-adapter on LAN 2s tunnel server. A dynamic range