To have stable networking, user "laxde2" found the following solution:

cp /usr/lib/lli/pnt/Space.c /usr/lib/lli/pnt/Space.c.org

Edit the "/usr/lib/lli/pnt/Space.c" file

Change:
#define TX_BUFFERS_0 16
#define RX_BUFFERS_0 16
 
To:
#define TX_BUFFERS_0 32
#define RX_BUFFERS_0 32

Save and close the file.
 
Now configure the network with the "netconfig" command:
Type in "netconfig" and press enter

Type "1" and press enter to add a chain.

Type "4" and press enter to add "SCO TCP/IP For Unix"

Type "13" and press enter to add "pnt0 - AMD PCNET Family Ethernet Driver, board 0"

Type "y" and press enter to continue

Press enter to detect the hardware automatically.

Type in the IP address for the adapter and press enter.

Type in the subnet mask for the adapter and press enter.

Press enter twice to accept broadcast address

Type "y" and press enter to continue.

Type in the local hostname or accept the default and press enter

Press enter to continue

Press enter to continue

Type "q" and press enter

Type "y" and press enter to relink the kernel

Type "y" and press enter to set default boot kernel

Type "y" and press enter to rebuild the kernel environment.

Add a default gateway:

Create the "/etc/gateways" file with the following content:

net 0.0.0.0 gateway <gateway IP address> metric 1 passive

Save and close the file.

Type "init 6" and press enter to reboot the new kernel.