On Ebay you may run across a good deal on a 100BaseT Nic card for a Sparc 20 (S bus). This will not help your Internet access, but might be useful within your home network. This article talkes about setting the card up.
There are two types of cards you may run across. The more common is the single high speed NIC card. The other is the quad card which has 4 RJ45 connectors. This one is a bit overkill for a home network unless you are using the Sun as your router. Before you shut down the machine to load the card, you will want to make two updates:
Shut down the machine and take the cover off using the two screws in the back. There are a bunch of blank covers on the back of the Sun. They use a really small Phillips head screwdriver. Take off one of these. Then insert the new card and attach it using the screws from the blank cover. Connect a CAT5 cable from the RJ45 connection to your router.
Close the machine up and power it on. While the memory check is going on, press
Stop-a (The stop key and letter A key at the same time) to interupt the boot
process. Then enter the command:
The machine will find the new interface. Watch the messages go by and you will see it detect and configure the new hme0 interface. When the system boots, you can use the ifconfig command to see the two interfaces. Verify that you can ping the new interface and get out on it. You can tell which interface is being used by watching the lights blink on the router.
To deactivate the le0 interface, rename the /etc/hostname.le0 file and reboot with the -r option. I renamed it to /etc/hostnameOFF.le0 to make it easy to find if I should want to reactivate it.