A free Basic UNIX-training with muLinux

The Internet

We concerned ourselves with the basic principles of networks. Now we turn to the largest network, the Internet. We already became acquainted with some logs of the lower network layers used in the Internet. We want to provide an overview of the application possibilities of the Internets here.

The information in the Internet is variously and extremely differently, there also quite special fields of knowledge, areas of life or hobbies to be considered. Since this supply in its whole is planned neither nor listed central, it is somewhat unclear.

Differently than the television that is Internet an interactive medium. Each Internet user is not inevitably only consumer, but can also as a " producer " occur. Who likes, the multiplicity of the supplies in the Internet can complete by own factories. Linux would not have developed without Internet surely.

At all that is closely linked Internet with Unix. Most computers, which serve in the Internet services (servers), base on Unix operating system. Linux plays thereby a large role.

History

The assumption is obvious, that to Internet is a result of extensive planning and designs. Far been missing. That was actually invented Internet not at the drawing board, let alone was not foreseen one the today's world-wide spreading. As the following short trip points to the past, the origin of the Internet is situated in the United States of the 60's.

The technological basis for Ur-Internet forms the ARPAnet . The Advanced Research project Agency (ARPA) is an authority of the Ministry of Defense of the USA. To be interconnected target was some universities it on the one hand fail safe data links for the army to be supplied and on the other hand to research purposes.

From this ARPAnet developed Internet the log ( IP ). for at the beginning of the 80's the military part of MILNET from the ARPAnet was separated. The remaining " remainder " was transferred to the universities for use.

Another authority of the US Government the National Science Foundation (NSF) gave the following six computing centres to end of the 80's the job to interconnect: national computing centre of the Cornell University of scientific computing department of the national center for atmosphere research in Boulder, Colorado computing centre of the university of California in San Diego national center for applications of large computers at the university of Illinois national John von Neumann computing centre in Princeton, new jersey computing centre in Pittsburgh (Westinghouse Electric Corp., Carnegie Mellon University of and university of Pittsburgh)

The NSFnet had been created primarily for research purposes. The IP developed by the ARPAnet (Internet log) was used. The commercial use was very disputed in first time. But now, where the support of the US Government ran out, commercial and not-commercial services on the network can be operated together. Which began with the networking of 6 large computing centres in the USA has now a scope of approx. 50 countries, more than 3 million host computers and 15 to 40 million users achieves. Internet is a constantly developing further network of computers and networks.

Services

This drawing represents two services. For example the email and WWW can be.

........................                  ........................
.                      .                  .   ________________   .
.   _______________    .                  .   |               |  .
.   |              |   .                  .   |               |  .
.   |              |   . Port        Port .   |               |  .
.   |    Client    |------------------------->|     Server    |  .
.   |              |<-------------------------|               |  .
.   |______________|   .                  .   |               |  .
.                      .                  .   |_______________|  .
.                      .                  .                      .
.                      .                  .   ________________   .
.   _______________    .                  .   |               |  .
.   |              |   .                  .   |               |  .
.   |              |   . Port        Port .   |               |  .
.   |    Client    |------------------------->|     Server    |  .
.   |              |<-------------------------|               |  .
.   |______________|   .                  .   |               |  .
.                      .                  .   |_______________|  .
.                      .                  .                      .
........................                  ........................
                             Netzwerk
     Client-Rechner          Internet          Server-Rechner

E-Mail

/ # mail

The muLinux version deviates in the operation somewhat from the Unix standard. The muLinux email program is left in addition, also q . Actually this Client is called rna . There is a set of email under Linux programs. So e.g. the very efficient program mutt . To dispatching Mail the SMTP log (simple Mail transfer log). We control whether this service are supported:

/# cat /etc/services | grep smtp
smtp   25/tcp mail
/# _

Smtp is thus addressed over port 25. For the receiving of email either the log serves POP3 (post office Office log) or the newer IMAP.

/# cat /etc/services | grep pop-3
pop-3   110/tcp   # PostOffice V.3
/# _

Usenet, Newsgroups

/# news

Over one link becomes as mail the program rna called. This program is thus Mail and News Client. With m can be changed between both modes. The log is called here NNTP (network News feed Protocoll).

/# cat /etc/services | grep nntp
nntp    119/tcp Usenet   # network News transfer
/# _

FTP

/# ftp

As FTP Client here that serves already well-known file managers pion. ftp is link thus here up pion. As we will also also know these q terminated.

/# cat /etc/services | grep ftp
ftp-data     20/tcp
ftp          21/tcp
tftp         69/tcp
sftp        115/tcp
/# _

SFTP (simple file Tranfer Protocol) and TFTP (trivial File Transfer Protocol) are simplified and uncertain file transmission protocols. " The correct " ftp communicates over port the 20 (data) and 21.

Gopher

WWW

The most well-known WWW Browser is Netscape, MSI MSI-Explorer and Opera. Fewer admits is lynx, a fast, text-based Browser. lynx becomes gives it for different operation systems. In older muLinux versions belonged lynxin addition. The developer of muLinux this Browser was excessive. Michele Andreoli programs probably everything briefly and small. He created quark.

/# quark

The log is called here HTTP (hypertext transfer Protocol) and communicates over port 80:

/# cat /etc/services | grep www
www      80/tcp      http      # WorldWideWeb HHTP
www      80/udp                # HyperText Transfer Protocol
/# _

IRC

/# irc
...

The Client is called here TinyIRC. Port 6667.

/# cat /etc/services | grep irc
irc       6667/tcp         # Internet Relay Chat
/# _

Telnet

***TRANSLATION ENDS HERE ***

Um sich über das Netzwerk in einen anderen Unix-Rechner einzuloggen dient Telnet. Nach Angabe seines Nutzernamens und des Paßwortes kann man mit der Kommandozeile arbeiten als säße man direkt an diesem Computer. muLinux kann hier sowohl Server als auch Client sein. Man kann sich also von einem anderen Rechner in seinem muLinux-Rechner einloggen.

/# telnet hostname
...

Normalerweise arbeitet Telnet mit dem Port 23.

/# cat /etc/services | grep telnet
telnet       23/tcp
/# _