Note: This article pertains to Mac OS X Server versions 1.x, which were released prior to May 2001.
This problem can have a variety of causes. Two possibilities are that the NetInfo database has been corrupted or the network interface card has been removed.
One solution is to rebuild the NetInfo database to a default configuration.
First, start up the computer in single-user mode.
The computer starts up to the single-user command line. Next, at the command line type these commands to copy a new NetInfo database and new hostconfig file:
# cp -rp /usr/template/client/etc/netinfo /etc
# cp -p /usr/template/client/etc/hostconfig /etc
This sets your computer back to a default NetInfo configuration as it was when you first installed Mac OS X Server. You can then use NetworkManager in /System/Administration to reconfigure the computer.
Warning: Creating a new NetInfo database may be a drastic measure under certain circumstances. If you've invested a lot of time configuring a NetInfo database, you probably want to rebuild it from scratch only as a last resort. If you feel this is your situation, ask an experienced Mac OS X Server system administration expert for help before replacing the database. A better choice might be to restore the /etc/hostconfig file and the contents of /etc/netinfo from backups made when the network was functioning properly.