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Section 3 Principles of Operation

Section 3 Principles of Operation
LISTSERV® is software that allows you to create, manage, and control electronic "mailing lists" on a corporate network or on the Internet. Since its inception in 1986 for IBM mainframes on the BITNET academic network, LISTSERV has been continually improved and expanded to become the predominant system in use today. LISTSERV is now available for VM, OpenVMS, several types of unix, and the Microsoft Windows "family" (including Windows 2000 and later).
Consider for a moment what the users of your electronic mail system actually use electronic mail for. Do they discuss problems and issues that face your organization, down to the departmental level? In an academic setting, do your faculty and students communicate via electronic mail? As with "real world" distribution lists, electronic mailing lists can make it possible for people to confer in a painless manner via the written word. The electronic mail software simply replaces the copying machine, with its associated costs, delays and frustrations. In fact, electronic mail lists are easier to use than most modern copiers, and a lot less likely to jam at just the worst possible moment.
Because electronic mail is delivered in a matter of seconds, or occasionally minutes, electronic mailing lists can do a lot more than supplement the traditional paper distribution lists. In some cases, an electronic mailing list can replace a conference call. Even when a conference call is more suitable, the electronic mailing list can prove a powerful tool for the distribution of papers, figures and other material needed in preparation for the conference call. And, when the call is over, it can be used to distribute a summary of the discussion and the decisions that were made. What before might have been an exchange of views between two or three people can now become an ongoing conference on the issue or problem at hand. Announcement lists and even refereed electronic journals can be made available to your audience, which can be as small as a few people or as large as the entire Internet community.
LISTSERV accomplishes its design goals very efficiently and very quickly. This is due primarily to its use of the proprietary DISTRIBUTE algorithm (described in RFC1429, and in the Advanced Topics Guide for LISTSERV, available separately) and to the large (and growing) network of LISTSERV servers.
The LISTSERV network of servers helps to enhance LISTSERV's performance by providing a "backbone" through which large quantities of mail can be quickly distributed. The backbone also allows LISTSERV servers to "talk" to each other and exchange information. Among other things, this exchange of information between servers allows your own local server to participate in the global List of Lists service and L-Soft's CataList service on the World Wide Web.
LISTSERV's nature as a distributed network of interconnected servers also makes it possible to identify and eliminate unsolicited advertisements sent to multiple lists (known as "spam") before they do much harm. While it is virtually impossible for a small isolated server to detect spam (unless the sender listed the thousands of lists he was targeting in the "To:" field), the LISTSERV network receives thousands of copies of the spam. By comparing notes with each other, the servers can quickly determine that a spam is occurring and raise a network-wide "spamming alert", stopping the message before it does much damage at all. Since the introduction of LISTSERV's anti-spam technology, the growing number of sites that are participating in the anti-spamming warnings have virtually stopped the distribution of such messages in their tracks. L-Soft is constantly upgrading and refining the anti-spam algorithms.
In addition to the anti-spamming filter, LISTSERV also incorporates an anti-spoofing filter, to keep mischievous (and often malicious) users from subscribing other users to mailing lists in order to "mailbomb" them.
LISTSERV makes it possible for you to offer the same mailing list in four different formats:
Individual mail messages sent out as they are processed
Digest mode, where a compendium of messages processed by the list is sent at specified intervals
Indexed mode, where an index consisting of the message number, sender, and the subject line of each message is sent each day, along with instructions on how to retrieve postings from the server
These modes are set by sending SET commands to LISTSERV. Unlike some other mailing list management systems, LISTSERV does not require the user to unsubscribe from one version of the list and resubscribe to another just to change delivery modes.
LISTSERV includes database search capability for list archive notebooks. A fast reverse indexing feature is available for servers running lists with large archives. Users can use a simple search syntax to comb list archives for specific terms of interest. And L-Soft provides a World Wide Web archive interface (not currently available on VM for technical reasons unrelated to LISTSERV itself) with which the notebook archives for all public lists can be viewed and searched from a web browser. LISTSERV's WWW interface differs from (and has advantages over) "hypermail" style web archiving in that new postings are shown as soon as they are received; postings can be organized in a manner that best suits the reader; there is no duplication of effort, as the LISTSERV WWW interface works from the list’s notebook archives rather than creating a separate HTML file for each posting; and the list owner can customize the main page for their list by simply modifying their mail template file.
LISTSERV also includes a number of list and server management functions in its WWW interface, including the ability to edit list headers and associated mail and WWW templates, and to manage subscribers via the Web. Almost every aspect of LISTSERV management, from the list subscriber level to the site administrator level, is available through the version 15 interface. See Section 11 Using the Web Administration Interface for details.
LISTSERV has contains DBMS and mail-merge support. These features are documented in the Advanced Topics Guide for LISTSERV, available separately. There is also much tighter tight integration between LISTSERV and L-Soft's campaign management software, LISTSERV Maestro, beginning with LISTSERV 15.0 and Maestro 3.0.
LISTSERV includes an Anti-Virus Scanning feature for messages passing through the server. This is a value-added enhancement which requires a special LAK and a special version of F-Secure Anti-Virus. At this writing the feature is only available for Windows 2000 and later, and Linux servers running LISTSERV Classic or LISTSERV Classic HPO. (Other OS platforms may be supported in the future; there is no intent to make this functionality available in the Lite version of the product.)
Many other enhancements have been introduced in LISTSERV 15.0. The full release notes are available at