TITLE: How to setup LINKSYS 4 port cable/DSL router and firewall

SAVED AS: how_to_setup_router_and_firewall.aw

DESCRIPTION: This summarizes the recommended setup for LINKSYS 4 port cable/DSL router and firewall.

MACHINE(s):

FILES:

NEED:

SCHEDULE:

FIRST DRAFT: Jan Mandel 05092001

REVIEWED BY:

This configuration allows to run all computers on a local network using only one external IP address assigned by your ISP. All connections to the outside will appear to come from that one IP address and the firewall will block all connections from the outside for security. Optionally, one Linux machine may be allowed to accept Secure Shell connections (see 4. below).

Configuration to open ports e.g. for online games is possible, refer to Linksys documentation, but it requires advanced understanding and needs to be done carefully so as not to disable to the protection afforded by the firewall.1.

1. Configure networking on all machines on the local network to "obtain IP address and DNS servers automatically" (Windows) or "obtain IP address and DNS servers by DHCP" (Linux).

2. Connect local machines by ethernet cables to the ports 1-4 and the external ethernet cable (e.g. from the cable or DSL modem) to the WAN port on the LINKSYS box.

3. Enter http://192.168.1.1 into a browser on one of the local machines and proceed with the setup according to the manual that came with the LINKSYS box. Configure only the WAN port according to the information from your ISP, leaving all else at defaults.

4. Optional: if you have a Linux machine on the local net that you want to log into remotely, set it instead of DHCP to the fixed IP address 192.168.1.2, default gateway 192.168.1.1, and DNS servers given by your ISP (132.194.10.3 and 132.194.10.4 if you connect through UCD, different if you have cable). After the basic configuration in 3. above, click on the "Advanced" tab, then on the "IP forwarding" tab, enter on the first line 22-22 for port numbers and 192.168.1.2 for the host IP address, click OK.

Note: you may have to turn the firewall off and on when you change settings for the settings to take effect.

Purchase info as of 2/6/01: LINKSYS part number BEFSR41, http://shop3.outpost.com/product/66841, $109.95