Mailing lists bring together people with similar interests to exchange information and ideas. Most mailing lists run under usage guidelines that restricted discussion to a specific topic. Mailing lists are often used as places to report problems and get solutions, or to receive announcements. Some mailing lists are digests of newsgroups.
There is an enormous number of mailing lists. The list-of-lists contains information about many of the mailing lists that are of interest to network administrators.  Use a Web browser to search for mailing lists that interest you at http://catalog.com/vivian/interest-group-search.html. If you prefer, the list-of-lists can be downloaded via anonymous FTP from nisc.sri.com in the file netinfo/interest-groups.txt and searched with standard UNIX tools. Either way, you get the same information. The following example is the list-of-lists entry for the Berkeley Internet Name Domain (BIND) software mailing list:
 Despite its large size, not every network administration mailing list is contained in the interest-groups.txt file. You hear about some lists by word of mouth.
BIND@uunet.uu.net Subscription Address: firstname.lastname@example.org Owner: BIND-REQUEST@UUNET.UU.NET Description: This list covers topics relating to Berkeley Internet Name Domain (BIND) domain software.
The entry has four sections: the address of the mailing list, the address to which subscription requests are sent, the address of the owner, and a description of the list.
When you find a list you wish to join, don't send mail directly to the list asking to be enrolled. Instead, send the enrollment request to the subscription address, which identifies the person or process that maintains the list. If the list is manually maintained, as in the BIND example above, send your enrollment request to list-name-request@host where list-name is the actual name of the list, and is followed by the literal string -request. The -request extension is widely used as the address for administrative requests, such as being added to or dropped from a list, when lists are manually maintained. For example, to join the BIND mailing list, send your enrollment request to email@example.com. All other correspondence is sent directly to firstname.lastname@example.org.
Many mailing lists automate list management with programs like majordomo and LISTSERV. You can tell the type of server being used by looking at the subscription address in the list-of-lists. The user portion of that address will be either "majordomo" or "LISTSERV," depending on the server being used. To subscribe to a majordomo list, send email to the subscription address and type the following in the body of the message:
list-address is the address of the email list, and
your-address is your email address.
To subscribe to a LISTSERV mailing list, send email to the subscription address with the following in the message body:
list is the name of the list, not necessarily its address,
as that name appears in the first line of its list-of-lists entry.
your-name is your first and last name. This is not your email
address. LISTSERV takes your email address from the email headers.
A mailing list is one way of distributing announcements and exchanging questions and answers, but it is not the most efficient way. A mail message is sent to every person on the list. It is sent immediately, and it must be stored on the local system until it is read. Thus, if there are 100 people on a list, 100 messages are sent over the network and stored at 100 receiving systems. Network news provides a more efficient method for distributing this kind of information. The information is stored around the network on, for most sites, one or two news servers. Therefore, instead of moving mail messages to every individual on your network who wants to discuss the Linux operating system, news articles about Linux are stored at one location where they can be read when the user is ready. Not only does this reduce the network load, it reduces the number of redundant copies that are stored on local disk files.
Network news is delivered over TCP/IP networks using the Network News Transfer Protocol (NNTP). NNTP is included as part of the TCP/IP protocol stack on most UNIX systems and requires no special configuration. The only thing you need to know to get started is the name of your closest network news server. Ask your ISP. Most ISPs provide network news as part of their basic service.
NNTP is a simple command/response protocol. The NNTP server listens to port 119:
telnet news.nuts.com 119Trying 172.16.16.19... Connected to news.nuts.com. Escape character is ']'. 200 news.nuts.com ready (posting ok). quit 205 Connection closed by foreign host.
UNIX systems often include a news reader. Our sample Linux system includes several different readers: nn, rn, tin, and trn. Your system may have anyone one of these or another newsreader. See the appropriate manpage for specific instructions on using a particular reader.
Regardless of the reader you have, they all have certain things in common. They all provide a way to subscribe to a news group, read articles from the group, and post your own articles to the group. In this trn example from our Linux system, the titles of the first 26 articles in the comp.os.linux.announce group are listed. To read an article, the user scrolls down to select the article and presses Enter. All readers provide a similar interface.
comp.os.linux.announce 50 articles (moderated) a root 1 Ringconnect b Clark 1 NTLUG Meeting d Dave 1 Caldera e Martin 1 Linux Users Group Meeting f Evan 1 COMDEX Canada g Jimn 1 Salt Lake Linux Users Group i Tyde 1 San Fransisco Linux users' group j Andy 1 Worcester Linux Users' Group l Bob 1 MELUG meeting o Olaf 1 IP tunnel r Norbert 1 Index files s Albert 1 Client-/Server-Backup t Michael 1 Parallel programming u Oz 1 FTP client v Ted 1 Important notice w Kamran 1 DIPC available x Ken 1 Web site y Cindy 1 CD-ROM available now! z Bishop 1 C program documentation tool -- Select threads (date order) -- Top 38% [>Z] --
Our sample Solaris system doesn't include any news readers mentioned above. But it doesn't matter. News is supported in the Netscape Navigator Web browser. Selecting Netscape News from the Windows menu in the Netscape browser opens a news reader. Figure 13.7 shows us reading news from comp.os.linux.
There are many, many newsgroups. Most of the newsgroups that are of interest to a network administrator are found in the comp category. comp.os contains sub-groups for various operating systems. comp.unix lists groups for various flavors of UNIX. comp.networks and comp.internet provide information about networks and the Internet. comp.security and comp.virus provide security information.