ifconfig -a gives me:
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:80 errors:0 dropped:0 overruns:0 frame:0
TX packets:80 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:6952 (6.7 Kb) TX bytes:6952 (6.7 Kb)
That clearly shows that the driver for the card is not loaded (or else you would
have seen eth0 mentioned).
Have you tried running
to see if that gives you eth0?
and setting up eth0 does not mean that eth0 is thereby ready to go. Configured yes, but loading the driver is either the task of the hotplug subsystem, or you add a "modprobe" command in the file /etc/rc.d/rc.netdevice
yourself if hotplug does not recognize the card for whatever reason. That file "rc.netdevice" may not yet exist by the way. If the Slackware installer had recognized your card it would have setup that file for you. So, let's do it now:
Add this single line to it:
And after saving the file, make it executable:
chmod +x /etc/rc.d/rc.netdevice
Now, try to reboot and see what happens.