First, you may not be able to do this without upgrading the SCO.
Many SCO systems were sold without the ability to do networking
other than serial. These are "Host" versions. If you run "custom"
or use the Software manager from the GUI, you will see you either
have "Host" or "Enterprise": if you only have Host, you'll need to
upgrade (if that is the case, run "uname -X" to get the version
number and number of users - you'll need that when you ask someone for pricing
on an "Enterprise" upgrade.
If you have one of the very old 3.2v4.x releases you will be
hard pressed to find nic cards that will work with those.
If you DO have 5.0.x Enterprise, what you need to do next is get
the most current driver for your version/card. Go to ftp://ftp.sco.com/pub/openserver5/drivers/
and select your version (from uname -X, the version is what follows
3.2) then "networks" and if there is a current driver for your
card, download it. Don't neglect this step: some of the newer cards
absolutely will not work unless you get these drivers.
You'll install the driver by putting its media image (A file or
files named VOL.000.00X) in (for example) /tmp. You'll then use
"custom" or the GUI Software Manager to install it: choose Install
New Software, From This Host, Media Images, and point it at the
directory where you installed the VOL file.
After that, "netconfig" or the GUI Network Manager will let you
add this card and assign an address to it.
Note: When adding a pci Network card to SCO OSR5, the card should just "pop up" with netconfig - you shouldn't get a whole list of cards to choose from. If it does not showjust one card, you probably do not have the right driver and should revisit ftp://ftp.sco.com/pub/openserver5/drivers/ to get it or do determine what card you might be able
to find that you CAN get a driver for.
The trick to using netconfig or any of the SCO admin ("scoadmin") tools in character mode is to understand that the TAB key moves between panes - so to move from a sub-pane back to the menus, hit TAB and vice-versa.
Another trick with PCI cards that SHOULD be recognized but aren't, is to use netconfig as though you were adding some other card manually (a card that doesn't actually exist), and then come back and delete that one, and finally ask it to add a new card again. For reasons I never understood, sometimes that silly procedure will cause it to find the pci card that it didn't notice before.
You'll find files under /usr/lib/netconfig related to all this.
Also use "hw -r pci" to see what is actually installed. Sometimes a minor bios difference matters and your driver
Sometimes - but only sometimes - you can plug in the DeviceNum, Function and Bus into netconfig and get a working card, but that's rare.
Once the card is configured, assigned an IP and linked into the kernel, you can reboot and have a working system. You should see the driver initialize during boot; if you miss that "hwconfig" will show you the messages again.
If you see portmapper errors, you are heading in the right direction as that's easily fixed (see the link).
The mysterious atl0
SCO has an "atl0" interface. It has an IP of 0.0.00 and a strange "127.0.0.0" netmask. It's used in virtual domains and according to What is atl0?:
"atl0" interface was introduced by the Internet FastStart stuff (SCO
Internet FastStart 1.0.0, 1.1.0, and then incorporated into OSR5.0.4).
Internally it is a second device running over the loopback interface,
same as "lo0". Its serves as an interface to which aliases can be
assigned, i.e. if you are using Internet FastStart's multi-IP
facilities. I believe it automatically adds "atl1" etc. if you need
more than 256 aliases.
The insane and probably illegal netmask of both lo0 and atl0 is a known
issue. It isn't known to actually cause any problems; it's just a weird