Intranet - An inhouse Web site that serves the employees of the enterprise. Although intranet pages may link to the Internet, an intranet is not a site accessed by the general public.

Broadcast – Such as Ethernet, any system attached to the network cable can send messages at any time

Token ring – such as FDDI (Fiber Distributed Data Interface), only on e system can send a message at a time. A Token (Special Message) is passed from one host to another around the ring.

                    Point to Point – Only two end points are involved.

LAN - (Local Area Network) A communications network that serves users within a confined geographical area. It is made up of servers, workstations, a network operating system and a communications link.

Ethernet – The most widely used LAN access method (Token Ring is the next most popular). Ethernet is normally a shared media LAN. All stations on the segment share the total bandwidth, which is either 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet) or 1000 Mbps (Gigabit Ethernet). With switched Ethernet, each sender and receiver pair have the full bandwidth.

It uses:

· Thick coaxial cable

· Twisted Pair

· Fiber optics

WAN - (Wide Area Network) A communications network that covers a wide geographic area, such as state or country.

Packets – Message sent by the computer that includes the address of the destination computer and the one who sent it.

Router - A device that forwards data packets from one local area network (LAN) or wide area network (WAN) to another. Based on routing tables and routing protocols, routers read the network address in each transmitted frame and make a decision on how to send it based on the most expedient route (traffic load, line costs, speed, bad lines, etc.).

 

Protocol – common language used by computers so that they can exchange information over networks. The protocol determines the format of the message packet.

TCP/IP - (Transmission Control Protocol/Internet Protocol) A communications protocol developed under contract from the U.S. Department of Defense to internetwork dissimilar systems. Invented by Vinton Cerf and Bob Kahn, this de facto UNIX standard is the protocol of the Internet and has become the global standard for communications.

UDP - (User Datagram Protocol) A protocol within the TCP/IP protocol suite that is used in place of TCP when a reliable delivery is not required. For example, UDP is used for realtime audio and video traffic where lost packets are simply ignored, because there is no time to retransmit. If UDP is used and a reliable delivery is required, packet sequence checking and error notification must be written into the applications

Other Protocols: SLIP (Serial Line Internet Protocol), PPP ( Point to Point Protocol), and PLIP (Parallel Line Internet Protocol)

The physical address of a computer in a network. On the Internet, a host address is the IP address of the machine. IE. 192.192.192.5 . The address assignments are handled by a central authority an organization named the Network Information Center (NIC)

Try visiting:

Find your own ip address http://www.ip-address.com/

$ finger - A UNIX command widely used on the Internet to find out information about a particular user, such as telephone number, whether currently logged on or the last time logged on. The person being "fingered" must have placed his or her profile on the system. Profiles can be very elaborate either as a method of social introduction or to state particular job responsibilities. Fingering requires entering the full user@domain address, if you have several machine on your network. Otherwise you will have to type user@domain.something to find information about a user located outside of your network.

 

$ hostname – Allows you to identify the system that you are using

[wmorales@rc33uxas01 wmorales]$ hostname

rc33uxas01

[wmorales@rc33uxas01 wmorales]$

$ ruptime - Show the status of local networked machines

$ rwho - The rwho command produces output similar to who, but for all machines on your network

$ mail – Send an email message to a user

$ talk – Allow to communicate interactively with a remote user over the network

 

$ rlogin – (Remote LOGIN) A UNIX command that allows users to remotely log onto a server in the network as if they were at a terminal directly connected to that computer. Rlogin is similar to the Telnet command, except that rlogin also passes information to the server about the type of client machine, or terminal

$ telnet - A terminal emulation protocol commonly used on the Internet and TCP/IP-based networks. It allows a user at a terminal or computer to log onto a remote device and run a program.

$ rsh - (Remote SHell) A UNIX command that enables a user to remotely log into a server on the network and pass commands to it. It is similar to the rlogin command, but provides passing of command line arguments to the command interpreter on the server at the same time

$ rcp - Rcp copies files between machines. Each file or directory argument is either a remote file name of the form ``rname@rhost:path'', or a local file name (containing no `:' characters, or a `/' before any `:'s).

$ rcp memo.921 bravo:memos/memo.921

The filename memo.921 is copied from the working directory on the local system to the memos directory on bravo

$ ftp (File Transfer Protocol) A protocol used to transfer files over a TCP/IP network (Internet, UNIX, etc.). For example, after developing the HTML pages for a Web site on a local machine, they are typically uploaded to the Web server using FTP.

$ ping (Packet INternet Groper) An Internet utility used to determine whether a particular IP address is online. It is used to test and debug a network by sending out a packet and waiting for a response.

$ netstat - The netstat command symbolically displays the contents of various

network-related data structures for active connections. The Interval

parameter, specified in seconds, continuously displays information

regarding packet traffic on the configured network interfaces.

$ traceroute - An Internet utility that traces the route from the client machine to the remote host being contacted. It reports the IP addresses of all the routers in between.

[wmorales@rc33uxas01 wmorales]$ /usr/sbin/traceroute psg.com

traceroute to psg.com (147.28.0.62), 30 hops max, 38 byte packets

1 198.106.33.10 (198.106.33.10) 0.527 ms 0.468 ms 0.492 ms

2 192.220.63.153 (192.220.63.153) 0.957 ms 0.870 ms 0.852 ms

3 192.220.63.33 (192.220.63.33) 3.238 ms 3.083 ms 5.888 ms

4 192.220.63.14 (192.220.63.14) 3.761 ms 4.339 ms 4.197 ms

5 192.220.63.6 (192.220.63.6) 6.370 ms 7.631 ms 5.948 ms

6 d1-1-0-0-28.a02.ptldor01.us.ra.verio.net (199.238.102.114) 7.023 ms 6.922 ms 8.161 ms

7 ge-1-0-0.r01.ptldor01.us.bb.verio.net (129.250.30.145) 7.236 ms 9.388 ms 7.480 ms

8 p4-4-2.r02.sttlwa01.us.bb.verio.net (129.250.3.37) 11.371 ms 11.391 ms 11.213 ms

9 et-3-0.o00.sttlwa01.us.bb.verio.net (129.250.31.130) 12.465 ms 11.917 ms 12.157 ms

10 psg.o00.sttlwa01.us.bb.verio.net (129.250.16.238) 16.618 ms 16.908 ms 18.347 ms

11 psg.com (147.28.0.62) 20.513 ms 16.346 ms 17.101 ms

[wmorales@rc33uxas01 wmorales]$

USENET - (USEr NETwork) A public access network on the Internet that provides user news and group e-mail. It is a giant, dispersed bulletin board that is maintained by volunteers who provide news and mail feeds to other nodes. All the news that travels over the Internet is called "NetNews," and a running collection of messages about a particular subject is called a "newsgroup." Usenet began in 1979 as a bulletin board between two universities in North Carolina. Today, there are more than 50,000 newsgroups. News can be read with a Web browser or via newsreaders such as nn, rn, trn and tin

Examples of news groups:

$ rn or.forsale to read the newsgroup or.forsale

ARCHIE - (ARCHIvE) An Internet utility used to search for file names. There are approximately 30 computer systems throughout the Internet, called "Archie servers," that maintain catalogs of files available for downloading from various FTP sites. Periodically, Archie servers search FTP sites throughout the Internet and record information about the files they find. If you do not have Archie, some Internet hosts let you log on via Telnet as user "archie."

$ archie (if archie is on local system)

$ telnet archie.uninett.no (to connect to an archie server)

GOPHER - A program that searches for file names and resources on the Internet and presents hierarchical menus to the user. As users select options, they are moved to different Gopher servers on the Internet. Where links have been established, Usenet news and other information can be read directly from Gopher. There are more than 7,000 Gopher servers on the Internet

$ gopher (it works at cyberspace)

If you use a web browser type for instance gopher://gopher.voa.gov/ at the address location on the top of your browser.

LYNX - A text-based Web browser created at the University of Kansas. Though largely supplanted by graphical browsers such as Netscape Navigator and Internet Explorer, Lynx is still popular among people with visual disabilities and those with very slow modem connections.

Unix text based version of a web browser

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This page was last modified September 26, 2004
wmorales@pcc.edu