As soon as multiple UNIX systems in a network want to access common resources, it becomes important that all user and group identities are the same for all machines in that network. The network should be transparent to the user: whatever machine a user uses, he always finds himself in exactly the same environment. This is made possible by means of NIS and NFS services. NFS distributes file systems over a network and is discussed in Section 21.10. “NFS — Shared File Systems”.
NIS (Network Information Service) can be described as a database-like service that provides access to the contents of /etc/passwd, /etc/shadow, and /etc/group across networks. NIS can also be used for other purposes (to make available the contents of files like /etc/hosts or /etc/services, for instance), but this is beyond the scope of this introduction. People often refer to NIS as YP, which simply stands for the idea of the network's “yellow pages.”
For the configuration, select master), you can add a NIS slave server (for example, if you want to configure a new subnetwork). First, the configuration of the master server is described.from the YaST module . If no NIS server existed so far in your network, activate in the next screen. If you already have a NIS server (a
If some needed packages are missing, insert the respective CD or DVD as requested to install the packages automatically. Enter the domain name at the top of the configuration dialog, which is shown in Figure 21.32. “YaST: NIS Server Configuration Tool”. With the check box, define whether the host should also be a NIS client, enabling users to log in and access data from the NIS server.
To configure additional NIS servers (slave servers) in your network afterwards, activate now. Select to set fast transfer of the database entries from the master to the slave server.
To allow users in your network (both local users and those managed through the NIS server) to change their passwords on the NIS server (with the command yppasswd), activate the corresponding option. This makes and available. “GECOS” means that the users can also change their names and address settings with the command ypchfn. “SHELL” allows users to change their default shell with the command ypchsh, for example, to switch from bash to sh.
By clicking 21.33. “YaST: Changing the Directory and Synchronizing Files for a NIS Server”, in which to change the source directory of the NIS server (/etc by default). In addition, passwords and groups can be merged here. The setting should be so the files (/etc/passwd, /etc/shadow, and /etc/group) can be synchronized. Also determine the smallest user and group ID. Press to confirm your settings and return to the previous screen. Then click ., access a screen, shown in Figure
If you previously enabled maps, the partial databases to transfer from the NIS server to the client. The default settings are usually adequate., enter the host names used as slaves and click . If you do not use slave servers, the slave configuration is skipped and you continue directly to the dialog for the database configuration. Here, specify the
21.34. “YaST: Setting Request Permissions for a NIS Server”. Specify from which networks requests can be sent to the NIS server. Normally, this is your internal network. In this case, there should be the following two entries:continues to the last dialog, shown in Figure
255.0.0.0 127.0.0.0 0.0.0.0 0.0.0.0
The first one enables connections from your own host, which is the NIS server. The second one allows all hosts with access to the same network to send requests to the server.
This module facilitates the configuration of the NIS client. After choosing to use NIS and, depending on the circumstances, the automounter, this dialog opens. Select whether the host has a fixed IP address or receives one issued by DHCP. DHCP also provides the NIS domain and the NIS server. For further information about DHCP, see Section 21.11. “DHCP”. If a static IP address is used, specify the NIS domain and the NIS server manually (see Figure 21.35. “Setting Domain and Address of NIS Server”). makes YaST search for an active NIS server in your network.
In addition, you can specify multiple domains with one default domain. Useto specify multiple servers including the broadcast function for the individual domains.