Running a NIS Server

After so much theoretical techno-babble, it's time to get our hands dirty with actual configuration work. In this section, we will cover the configuration of a NIS server. If there's already a NIS server running on your network, you won't have to set up your own server; in this case, you may safely skip this section.

Note that if you are just going to experiment with the server, make sure you don't set it up for a NIS domain name that is already in use on your network. This may disrupt the entire network service and make a lot of people very unhappy, and very angry.

There are currently two NIS servers freely available for , one contained in Tobias Reber's yps package, and the other in Peter Eriksson's ypserv package. It shouldn't matter which one you run, regardless of whether you use NYS or the standard NIS client code that is in libc currently. At the time of this writing, the code for the handling of NIS slave servers seems to be more complete in yps. So if you have to deal with slave servers, yps might be a better choice.

After installing the server program (ypserv) in /usr/sbin, you should create the directory that is going to hold the map files your server is to distribute. When setting up a NIS domain for the brewery domain, the maps would go to /var/yp/brewery. The server determines if it is serving a particular NIS domain by checking if the map directory is present. If you are disabling service for some NIS domain, make sure to remove the directory as well.

Maps are usually stored in DBM files to speed up lookups. They are created from the master files using a program called makedbm (for Tobias' server) or dbmload (for Peter's server). These may not be interchangeable. Transforming a master file into a form parseable by dbmload usually requires some awk or sed magic, which tend to be a little tedious to type and hard to remember. Therefore, Peter Eriksson's ypserv package contains a Makefile (called ypMakefile) that does all these jobs for you. You should install it as Makefile in your map directory, and edit it to reflect the maps you want to distribute. Towards the top of the file, you find the all target that lists the services ypserv is to offer. By default, the line looks something like this:

If you don't want to produce the ethers.byname and ethers.byaddr maps, for example, simply remove the ethers prerequisite from this rule. To test your setup, it may suffice to start with just one or two maps, like the services.* maps.

After editing the Makefile, while in the map directory, type ``make''. This will automatically generate and install the maps. You have to make sure to update the maps whenever you change the master files, otherwise the changes will remain invisible to the network.

The next section explains how to configure the NIS client code. If your setup doesn't work, you should try to find out whether any requests arrive at your server or not. If you specify the -D command line flag to the NYS server, it prints debugging messages to the console about all incoming NIS queries, and the results returned. These should give you a hint as to where the problem lies. Tobias' server has no such option.