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In the previous chapter we introduced the concept of a Network. We explained that it's equivalent to connecting to the local machine world.futuretg.com or to the Internet server, ftp://ftp.futuretg.com.
By "Internet" we mean the global network; that is the international network that connects all the organizations around the world. By "Web" or "World Wide Web" we mean all the information available on this network.
In this chapter we want to complete the previously introduced topics about the Internet as well as to introduce new ones like "traceroute" and other graphical programs that let you find programs or information like "xarchie", "xftp" or others.
RedHat Linux also includes Netscape Communicator (see Appendix N) and the Star Office suite (see Appendix S) that lets you use all the services available on the Web.
We will explain how to access the Internet through ISDN configuring Teles S0/16.3 and how to expand the Internet speed connection by adding a satellite connection.
Internet like an Intranet extension
In the section An Intranet session in the previous chapter we showed how to connect to the machine on the network using the FTP or telnet services.
We also explained that the connection to a local
network address like: world.futuretg.com (128.1.1.60) or a remote one (128.102.33.36,
naic.sasa.gov) is completely equivalent :
[root@heaven /root]# ftp naic.nasa.gov
Connected to nic.nasa.gov.
220 nic.nasa.gov FTP server (Version wu-2.4(2)
Sun Jul 28 15:54:19 PDT 1996) ready.
Name (naic.nasa.gov:root): anonymous
331 Guest login ok, send your complete
e-mail address as password.
Password:
230----------------------------------------------------------------------------
230-Welcome to the NASA Network Information
Center FTP Archive
230-
230- Access to
the NASA NIC's online services is also available through:
230-
230- World-Wide-Web
- http://nic.nasa.gov/nic/
230-
230-
If you experience any problems please send email to
230-
230-
nic@nasa.gov
230-
230-
or call +1 (800) 858-9947
230----------------------------------------------------------------------------
230-
230-Please read the file README
230- it was last modified on Mon
Oct 20 14:42:21 1997 - 378 days ago
230 Guest login ok, access restrictions
apply.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> cl
221 Goodbye.
ftp> o world
Connected to world.futuretg.com.
220 world.futuretg.com FTP server (Version
wu-2.4.2-academ[BETA-15](1) Wed Jan 7 01:03:55 MST 1998) ready.
Name (world:root):
331 Password required for root.
Password:
230 User root logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>
And that is also possible to connect from one network machine to another without any problems in a very easy and simple way.
We can also log into a local machine through the
Internet as we show in the figure :
We only have to know the address assigned by the ISP dynamically or the fixed one assigned by InterNic.
The connection from the world machine to Internet using the analog line "ppp0" shows this dynamic IP:
[root@world /root]# ifconfig ppp0
ppp0 Link
encap:Point-to-Point Protocol
inet addr:212.216.97.41 P-t-P:151.99.103.186 Mask:255.255.255.0
UP POINTOPOINT RUNNING MTU:1524 Metric:1
RX packets:10 errors:0 dropped:0 overruns:0
TX packets:10 errors:0 dropped:0 overruns:0
[root@world /root]#
Our IP address assigned by the ISP is 212.216.97.41. Therefore, any other computer or system connected to the Internet can connect with our system using this address:
[root@heaven /root]# telnet 212.216.97.41
Trying 212.216.97.41...
Connected to 212.216.97.41.
Escape character is '^]'.
Red Hat Linux release 6.0 (Hedwig)
Kernel 2.2.5-15 on an i686
login: root
Password:
Last login: Sun Sep 26 20:38:50 on :0
Love is Real
Real is Love
John Lennon
You have new mail.
[root@redhead /root]#
In this way we can enter into a local network machine "passing" by the Internet. This example is very useful in a commercial setting:
As we can see, the only important difference between
the local machines and the Web server is the IP address and the domain
name. The organization that assigns these numbers on a worldwide basis
is Internic,
http://www.networksolutions.com:
The Internet society, which controls Internet development, can be browsed at: http://www.isoc.org
Internic assigns a name and two unique IP addresses (the main one and an alternative one if the first fails) at the international level. Commercial companies have the suffix (.com), the Internet Service Provider (.net), the military organization (.mil), the government (.gov), organizations with humanitarian purposes (.org). In other cases the companies have the country suffix that explains the company target.
The ISP can also register other domains that have an Internet connection to its server.
These are some of the"domain names" present on Internet:
FTLinuxCourse also includes a copy of its FTYellowPages, a quick guide to the Web. Among these pages isWorld.html, which lists all the possible Internet suffixes for countries.
Afterwards it will be the ISP or the organization itself that activates the services that have to be offered:
As we explained in the previous chapter the most common Internet services have been available for some years. The big difference nowadays is the HTML language and the httpd daemon that displays images, texts, sound in a convenient and innovative way when we browse the Web.
The HTTP standard, Hypertext Transfer Protocol, was written by T. Berners-Lee and other people, in rfc1945, in 1996 in a formal way because Apple introduced this concept some years before.
The HTTP protocol is a protocol that lets you send images, texts and sound between machines where the httpd "daemon" runs:
The apache httpd daemon is installed in RedHat Linux from its first version.
To verify that this "daemon" we can run the command:
[root@heaven /root]# ps x | grep httpd
502 ? S
0:00 httpd -f /etc/httpd/apache/conf/httpd.conf
To activate this service on RedHat we can run the command:
[root@heaven /root]# ntsysv
Our FTLinuxCourse uses the httpd daemon for browsing and seeing images and texts.
The local activation of this daemon lets you send httpd requests locally. Remote requests are supported by the httpd daemon on the remote machine. In fact, the Netscape Communicator program handles all these requests.
Summarizing, if you send httpd requests, these are handled by the remote httpd, not by the local one .
The most used daemon for Web Servers, that is machines where HTML pages reside, is the Apache Web Server. The number of Apache servers is in first place with 52.31% market share and a total of 1,576,517 Web Servers installed. (These numbers are from before August 1998, when Linux entered into a safe place in companies) :
Apache was born from a free project developed by Rob McCool at the National Center for Supercomputing Applications an the University of Illinois, Urbana-Champaign. It was completed in 1995, corrected and updated by various people working at home.
Today the Apache team has 23 people who continue its development and enhancement.
The combination of Linux and Apache Web Server has opened the "freeware" season in the IT market.
To read the documentation and the history of Apache, see the document ABOUT_APACHE in the Web.
There are other sites that offer plug-in modules and information about Apache:
