Failure of clients to loginto a Linux NIS domain
1) First check that you can ping the server from the client. If not Check cables and nics.
2)If the NICs and cables are still good then go to the server(physically or through telnet) and check to see if the ypservices are running(ps -ef). If they are there then you have other problems not covered in this paper. If they are not then run ntsysv If you are on Redhat Linux. If not then you should check the rc*.d folders to see if there is an entry for yp and portmapper that begins with an S. In ntsysv check that yp and portmapper are selected, if they are not then select them. On other server types edit your run levels to include a start for yp and portmapper. Once these are done you need to reboot the system and check to see if they are now running.