No Server Available

If your domain name is set correctly, ypbind is running, and you get messages indicating that the client cannot communicate with a server, this may indicate a number of different problems:

• Does the client have a /var/yp/binding/domainname/ypservers file containing a list of servers to bind to? If not, run ypinit -c and specify in order of preference the servers that this client should bind to.

• If the client does have a /var/yp/binding/domainname/ypservers file, are there enough servers listed in it if one or two become unavailable? If not, add additional servers to the list by running yppinit -c.

• If none of the servers listed in the client's ypservers file are available, the client searches for an operating server using broadcast mode. If there is a functioning server on the client's subnet, the client will find it (though performance may be slowed during the search). If there are no functioning servers on the client's subnet can solve the problem in several ways:

  • If the client has no server on the subnet and no route to one, you can install a new slave server on that subnet.

  • You can make sure your routers are configured to pass broadcast packets so that the client can use broadcast to find a server on another subnet. You can use the netstat -r command to verify the route.

  • If there should be a route, but it is not working, make sure that the route daemon in.routed/in.rdisc is running. If it is not running, start it.

For reasons of security and administrative control it is preferable to specify the servers a client is to bind to in the client's ypservers file rather than have the client search for servers through broadcasting. Broadcasting ties up the network, slows the client, and prevents you from balancing server load by listing different servers for different clients.

• Do the servers listed in a clients ypservers file have entries in the /etc/hosts file? If not, add the servers to the NIS maps hosts input file and rebuild your maps by running yppinit -c or ypinit -s as described "Working With NIS Maps".

• Is the /etc/nsswitch.conf file set up to consult the machine's local hosts file in addition to NIS? See Chapter 2, The Name Service Switch for more information on the switch.

• Is the /etc/nsswitch.conf file set up to consult files first for services and rpc?