This chapter covered several important TCP/IP network services.
Network File System (NFS) is the leading TCP/IP file-sharing protocol for Unix systems. It allows server systems to share directories with clients that are then used by the clients as if they were local disk drives. NFS uses trusted hosts and Unix UIDs and GIDs for authentication and authorization.
Unix printer sharing is available on a TCP/IP network through the use of the Line Printer Daemon (LPD) or the Line Printer (LP) server. The lpd software is originally from BSD Unix but is widely available. The lpd program reads the printer definitions from the printcap file. The LP software is originally from System V. It uses terminfo for printer capabilities and the /etc/lp directory to configure individual printers. Solaris 8 printer sharing is based on the LP software but it configures printers in a single file, /etc/printers.conf.
Windows PCs use NetBIOS and Server Message Block (SMB) protocol for file and printer sharing. Unix systems can act as SMB servers by using the Samba software package. Samba provides file and printer sharing in a single package that is configured through the smb.conf file.
Network Information Service (NIS) is a server that distributes several system administration databases. It allows central control and automatic distribution of important system configuration information.
Dynamic Host Configuration Protocol (DHCP) extends BOOTP to provide the full set of configuration parameters defined in the Requirements for Internet Hosts RFC. It also provides for dynamic address allocation, which allows a network to make maximum use of a limited set of addresses.
Large networks use distributed boot servers to avoid overloading a single server and to avoid sending boot parameters through IP routers. The configuration files on distributed boot servers are kept synchronized through file transfer, NFS file sharing, or the Remote File Distribution Program (rdist).
Post Office Protocol (POP) and Internet Message Access Protocol (IMAP) servers allow email to be stored on the mail server until the user is ready to read it. In the next chapter, we take a closer look at configuring an electronic mail system as we explore sendmail.