4.11 TCPIP problems

I configured TCPIP on a NetWare 4.11 server yesterday. I enabled the TCP/IP protocol and bound TCP/IP to the card. I reboot the server and was able to ping it. Today I am not able to ping it. What could have happened and what do I need to check?

Under Protocols:
Enabled TCP/IP status, IP Packet Forwarding enabled Router, RIP enabled, everything else is disabled.

Under Bindings:
the IP address listed
subnetwork mask of connected network: FF.FF.FF.0

RIP Bind options:
shows NIC card
status enabled, RIP mode RIPI

Expert TCP/IP Bind options:
Use of ARP enabled
Force proxy ARP diabled