Now, we'll configure the router by editing /etc/network.conf. There are twelve changes to be made, as outlined below. Begin by opening the file: still in lrcfg, type 'q' a couple of times to get up to the top level (relaunching it if you accidentally quit the whole thing) and type '1' ("Network settings") then '1' ("Network Configuration (auto)") to launch ae.

In discussing the changes to /etc/network.conf below, I've put what you'll see from the stock file in the left column, and the changes I made in the right, in the order in which they appear in the file. You'll need to make similar changes.

1. Set the MAX_LOOP variable to two. We're only using two Ethernet cards.

   Original file	My file
   MAX_LOOP=6	MAX_LOOP=2

2. Turn on IP forwarding. That's what you want a router for, right?

   IPFWDING_KERNEL=NO IPFWDING_FW=NO

   IPFWDING_KERNEL=YES IPFWDING_FW=YES

   
   
   

3. Might as well give your router a more interesting name than "myrouter". You'll assign the actual name later.

   CONFIG_HOSTNAME=NO

   CONFIG_HOSTNAME=YES

4. Turn on DNS.

   CONFIG_DNS=NO

   CONFIG_DNS=YES

   
   
   

5. Enable and configure the ethernet interface that'll talk to the cable modem and the outside world. Uncommenting makes the configure script pay attention to it. The rest of the numbers are provided by your ISP (or like the broadcast address, inferable. The broadcast address is the same as your IP address in those segments where the netmask is 255, and is 255 in those segments where your netmask is 0. So if my netmask were 255.255.0.0 my broadcast address would be 111.222.255.255.)

   #IF0_IFNAME=eth0 IF0_IPADDR=192.168.1.194 IF0_NETMASK=255.255.255.192 IF0_BROADCAST=192.168.1.255

   IF0_IFNAME=eth0 IF0_IPADDR=111.222.33.254 IF0_NETMASK=255.255.255.0 IF0_BROADCAST=111.222.33.255

6. Enable and configure the ethernet interface that'll talk to your internal network. Be sure to use an address that's meant for networks that won't ever be connected to the net (rather than one that might conflict with someone else's legitimate IP address). You'll certainly want to choose one of the Class C addresses, so your netmask will be unchanged and your broadcast address will have a single 255.

   #IF1_IFNAME=eth1 IF1_IPADDR=192.168.2.1 IF1_NETMASK=255.255.255.0 IF1_BROADCAST=192.168.2.255

   IF1_IFNAME=eth1 IF1_IPADDR=10.0.128.1 IF1_NETMASK=255.255.255.0 IF1_BROADCAST=10.0.128.255

7. Uncomment and configure the IP address of the host (gateway) your eth0 interface will be talking to. This is the gateway address you got from your ISP. It's likely but not certain that like mine it'll be the same as your static IP address but with a 1 as the last segment.

   #HOST0_IPADDR=192.168.7.123 HOST0_GATEWAY_IF=default HOST0_GATEWAY_IP=192.168.1.200

   HOST0_IPADDR=111.222.33.1 HOST0_GATEWAY_IF=default HOST0_GATEWAY_IP=111.222.33.1

8. Uncomment and configure the network address of the network your IP address is on. This will usually be your IP address with the last segment replaced with a 0.

   #NET0_NETADDR=192.168.1.192

   NET0_NETADDR=111.222.33.0

9. Add a section configuring the network your second Ethernet card is on -- your internal network. NET1_NETADDR will almost certainly be the same as IF1_IPADDR but with the last segment 0 instead of 1.

   nothing nothing nothing nothing nothing nothing

   NET1_NETADDR=10.0.128.0 NET1_NETMASK=$IF1_NETMASK NET1_GATEWAY_IF=default NET1_GATEWAY_IP=default NET1_IPMASQ=YES NET1_IPMASQ_IF=default

10. Uncomment the line telling the config scripts that your ISP's gateway and host are the same. This is the most common case but may not always be true.

    #GW0_IPADDR=$HOST0_IPADDR

    GW0_IPADDR=$HOST0_IPADDR

11. Give your router a name -- since you said above that you would.

    HOSTNAME=myrouter

    HOSTNAME=pauling

12. Enter the DNS server[s] your ISP told you to use.

    DNS0=192.168.1.1 DNS1=192.168.1.2

    DNS0=24.1.4.12 DNS1=24.1.4.14