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[Chapter 13] 13.5 Mailing Lists

[Chapter 13] 13.5 Mailing Lists

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[Chapter 13] 13.5 Mailing Lists

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
subscribe list-address your-address
where 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:
subscribe list your-name
where list is the name of the list, not necessarily its address, as that name appears in the first line of its listof-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.

13.5.1 Newsgroups
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 119
Connected to news.nuts.com.
Escape character is ']'.
200 news.nuts.com ready (posting ok).
Connection closed by foreign host.
A help command sent to this server would have produced a list of 23 NNTP commands. Luckily this is not
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[Chapter 13] 13.5 Mailing Lists

how you read network news. You use a newsreader.
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.



50 articles (moderated)

NTLUG Meeting
Linux Users Group Meeting
Salt Lake Linux Users Group
San Fransisco Linux users' group
Worcester Linux Users' Group
MELUG meeting
IP tunnel
Index files
Parallel programming
FTP client
Important notice
DIPC available
Web site
CD-ROM available now!
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.
Figure 13.7: Netscape news interface

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[Chapter 13] 13.5 Mailing Lists

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.
There is a tremendous amount of dross in most news groups. But if you need a question answered or
information on a specific topic, they can be invaluable.

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[Chapter 13] 13.5 Mailing Lists

Previous: 13.4 Retrieving
13.4 Retrieving RFCs

TCP/IP Network
Book Index

Next: 13.6 The White Pages
13.6 The White Pages

[ Library Home | DNS & BIND | TCP/IP | sendmail | sendmail Reference | Firewalls | Practical Security ]

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[Chapter 13] 13.6 The White Pages

Previous: 13.5 Mailing Lists

Chapter 13
Internet Information

Next: 13.7 Summary

13.6 The White Pages
archie helps you locate important programs. The Web helps you retrieve important documents. whois
helps you locate important people. One of the most important pieces of information in a network is who is
in charge at the other end. In Chapter 11, Troubleshooting TCP/IP , we pointed out that it is important to
know who is responsible for the other end of the link when troubleshooting a network problem. whois is a
tool that helps you find this out.
whois obtains the requested information from the Internet white pages. The white pages is a database of
information about responsible people that is maintained by the InterNIC. When you request an official
network number or domain name, you are asked to provide your NIC handle, which is the index of your
personal record in the white pages database. If you don't have a handle, the InterNIC assigns you one and
automatically registers you in the white pages. Because of this, everyone who is responsible for an official
network or domain has an entry in the white pages, and that entry can be retrieved by anyone who needs to
contact them.
Many UNIX systems provide a whois command to query the InterNIC white pages. The general form of
this command is:
% whois [-h server] name
The name field is the information to be searched for in the white pages database. The server field is the
name of a system containing the white pages. Use rs.internic.net to locate responsible people, which is the
default on most systems.
In the following example, we search for an entry for Craig Hunt. An individual's name is entered in the
white pages as: last-name, first-name initial. So we ask to search for Hunt, Craig. [5]
[5] whois hunt would return several matches. Be as specific as possible to reduce the
number of matches.
% whois 'Hunt, Craig'
Hunt, Craig (CH999)
+1 (123) 555 6789
Hunt, Craig W. (CWH3) Hunt@ENH.NIST.GOV
(301) 975-3827
To single out one record, look it up with "!xxx", where xxx is the
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[Chapter 13] 13.6 The White Pages

handle, shown in parenthesis following the name, which comes first.
The InterNIC Registration Services Host contains ONLY Internet
Information (Networks, ASN's, Domains, and POC's).
Please use the whois server at nic.ddn.mil for MILNET Information.
If multiple matches are returned, as in this case, follow with a query for the individual's NIC handle to get
the full information display. To query for the NIC handle, which is the field enclosed in parentheses
directly following the username, simply enter the handle on the whois command line. The message at the
end of the sample output implies that handles are entered as !xxx. This is not true. The UNIX whois
command does not require the ! syntax. For example, to get more details about CWH3, enter:
% whois cwh3
Hunt, Craig W. (CWH3)
National Institute of Standards and Technology
Computer Systems and Communications Division
Technology Building, Room A151
Gaithersburg, MD 20899
(301) 975-3827 (FTS) 879-3827
Record last updated on 03-Dec-90.
Database last updated on 15-Jul-97 04:35:06.
User information is generally only useful if you know exactly who you want to send email to and you don't
know his or her address. The white pages database contains several other kinds of records, a few of which
are very helpful for locating the people responsible for networks, domains, and hosts throughout the
Internet. These record types are:
Provides detailed contact information for the people responsible for the specified domain.
Provides detailed information for the contacts for the specified network.
Provides general information about the specified host. This record type is not as useful as the others.
These record types can be used in the whois query to speed processing and limit the amount of output. All
of the record types shown above can be abbreviated to their first two letters.
A sample query for the domain ora.com produces the following results:
% whois 'do ora.com'
O'Reilly & Associates (ORA-DOM1)
101 Morris Street

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