9.6. Managing Distributed Servers

Large networks have multiple servers. As noted earlier, the servers are often distributed around the network with a server on every subnet. This improves network efficiency, but it conflicts with the goal of central configuration control. The more servers you have, the more dispersed the control, and the more likely that a configuration error will occur. Implementing distributed servers requires a technique for maintaining central control and coordinating configuration information among the servers. TCP/IP offers several techniques for doing this.

Any file transfer protocol can be used to move configuration data or any other kind of data from a central system to a group of distributed systems. Either FTP or TFTP will work, but both present difficulties when used in this way. FTP and TFTP are interactive protocols, and require multiple commands to retrieve a file, making them difficult to script. Additionally, FTP requires password authentication before it grants access to a file, and most security experts frown on storing passwords in scripts. For these reasons, we don’t concentrate on using these protocols to distribute the configuration file. Besides, if you know how to use FTP (and you should!), you know how to use it to send a configuration file.