Common Computer Terminology

Address - a data field in a packet header that specifies either the sender or the intended receiver of the packet.  Note that computers can often see data packets that are not intended for them.

Administrator - the person responsible for computer coonfigurations and support.

Allow/Block (Packets) - the action of receiving a packet.  Block means the packet is not sent/received.  Allow means it is sent/received.

ARP - Address Resolution Protocol

BO - short for "Back Orifice", a Trojan remote control program. This program was designed to illustrate the serious security breaches that are possible when using the Windows operating systems and, indeed, it has been used to cause a lot of mischief and damage. (BO's default setup is to listen on UDP port 31337. There are many programs available to detect the standard version of BO - some free.)

BRKill - an attack program that exploits a security weakness in the behaviour of Microsoft's implementation of TCP/IP. Starting with your IP address and a good guess of a TCP connection you have running (particularly easy when on IRC or using PPTP), the attack finds the TCP packet sequence numbers and then attempts to close the connection by spoofing a "disconnect" packet.

Button - an item on a window that causes an action to be performed when it is "pressed", (usually by clicking the mouse button when the cursor is on it).

Connection - a method of data exchange that allows a reliable transfer of data between two computers.

Cookie - a file placed on your hard drive by a web site you visit. The original intent was for cookies to contain information about your preferences, so they can tailor the appearance to your wants. This will save time when you next visit the site.{The security risk with cookies is that, since they are written directly to the hard drive, they can store something dangerous (a virus) or private (a password).  There is also concern that one website can get a cookie created by another website.   It appears that cookies cannot be used to get other data from a user's hard drive (such as, applications used, database, address book, personal files, etc.).  Cookies can, on the other hand, be used to track where a user has been within a web site.} (Netscape Navigator and Internet Explorer can be set to ask you whether or not you will accept a cookie.  I suggest you do not allow cookies unless you have a reason for doing so.)

Default (settings) - the configuration and behavior on installation, before any changes are made.

DHCP - Dynamic Host Configuration Protocol

D.I.R.T. - Data Interception by Remote Transmission. It is intended to be a law enforcement tool for gathering evidence for criminal investigations - the software equivalent to bugging a room.

DNS - Domain Name Service, a service for mapping computer names to their IP Address. 

Email - electronic mail, a method of sending messages to other people via computer networks.

Ethernet - the most common type of local area network (LAN), transmits at 10 or 100 Mbps.

Fileshare - a file system resource available through a network connection.(Your system uses UDP broadcasts to announce its presence on a network and listens to see who is out there.  This is alright in a trusted office environment, but is completely inappropriate for an Internet connection.)

Finger - a service that finds information about a user.

FTP - File Transfer Protocol.  A method of sending and receiving files over the internet.  Can be used through a browser, DOS prompt, or third party program, such as CuteFTP.   Example: FTP://www.sampleftpsite.com. For a much better F.T.P. go to downloads

GRE - Generic Routing Encapsulation. This protocol is used by PPTP.

Hacker - there are many definitions. The one used here is a a person whose intentions are to learn as much about security protocals as possible, sometimes resorting to “breaking into” systems operated/administered by persons other than themselves.  Commonly, however this term is incorrectly used to describe someone who misuses computer resources, often finding or damaging information.

HTTP - Hyper Text Transfer Protocol.  Used to transfer html(webpages like the one you are looking at) and images.  Example: http://www.samplehttpsite.com

HTTPS - Secure HTTP.   This is a variation of HTTP that uses encryption to add privacy.  The latest encyrption level is 128-bit, which is huge.(Don't do online banking and credit card transactions without secure measures such as this.)

ICMP - Internet Control Message Protocol, a maintenance protocol that handles error messages and helps network debugging. ICMP is carried in IP packets.
(ICMP is easily abused and has become a serious annoyance to IRC chatgroup users. Because other people can find out information about you, such as your IP address, they can easily send false ICMP messages to your system, causing it to promptly drop your IRC connection.)

Identification - a service that provides user information to another system, so they can try to verify your identity.  If you block it, other systems (such as email servers) may refuse you their services.  (This service is also known as "ident" or "auth".)

Inbound packet - a packet arriving from a remote computter or network

IP - the essential network protocol of the Internet.  It supports TCP, UDP, ICMP and many others.  I recommend getting a program which filters TCP, UDP and ICMP, and who’s System Settings allow you to allow or block the remaining protocols.

IPX/SPX - a network protocol, most commonly used by Novell.  Also, it can be tunneled over IP.  (I suggest you run a program such as ConSeal Private Desktop to effectively block IPX and other non-IP protocols.

IRC - Internet Relay Chat.  A service that lets people on the Internet share a typed conversation.  Whatever a person typed is sent to other people in the "chat group".(The risk here is that people might become hostile and try to "nuke" you or send you unpleasant email.  Consider NetNanny to screen the messages that are sent in IRC.There are some very nasty people on IRC, including pedophiles and "cyberstalkers".)

ISP - Internet Service Provider, the company that sells you access to the Internet.

Listening - TCP connections are made to a "listening" port that is ready to accept an incoming connection. The icon for a listener in the Activity Tree is usually an ear.

Log File - a record kept to track activity.  The log file helps monitor what your computer has done and helps to troubleshoot problems, whether they are hacking related or not.

Menu - a list of commands that are available..  If a command is in gray, it is not available.

Modem - a device that sends and receives data over a connection, most commonly over POTS(plain old telephone system), cable, ADSL or ISDN.   Most are analog rather than digital.

NetBEUI - NetBIOS Extended User Interface.  A local-area protocol that operates underneath the NetBIOS interface.

NetBus - a program designed to install without the user knowing about it and allow remote control of the system, including keyboard logging and file access.  (NetBus uses TCP ports 12345 and 12346 by default.)

Netware-IP - A Netware protocol sent using the IP pprotocol.

Network Device - a hardware computer component that connects your computer to a network, such as Ethernet or Internet.

News (NNTP) - a service available through most ISPs where thousands of newsgroups discuss specific topics, and users may post relevant articles.{Remember that anything you post will be archived permanently and can be retrieved at such website as www.dejanews.com. Also, if you post using your real email address, you WILL receive an unending stream of "spam" (junk email).}

Operating System - the low-level program that supports the running of all other programs on a computer.  OS/2, Linux and Windows are operating systems.

Outbound Packet - a packet leaving your computer or network to a remote destination.

Packet Filter - a function of a firewall that checks inbound and outbound packets, and depending on predefined rules, allows or blocks them.

Password - a secret character sequence used for authentication.(Passwords can be stolen by trojans such as BO, NetBus and D.I.R.T.  For better security, consider token-based authentication or one-time passwords.)

Ping - an ICMP-based service used to verify the availability of computers on a network.  Example in DOS: ping 127.0.0.1 or ping www.samplewebsite.com

POP2 - Post Office Protocol, version 2.  Used to transfer email

Port - a number used by protocols such as TCP and UDP to identify a communication instance.

PPP - Point-to-Point Protocol, a low-level protocol used to transport higher-level protocols such as IP.

Print Share - a printer resource available through a network connection.

Protocol - a standardized method of communicationn, e.g. IP.

RAS - Remote Access Service, a service that supports dial-up connections.

Remote (Address or Port) - refers to another machine you might communicate with, as opposed to your (local) machine.

Router - A peice of hardware that connects networks to other networks, or the internet.

Service - an application or function often considered part of the operating system.  Essential to Windows NT Server

SLIP - Serial Line Internet Protocol, a predecessor to PPP.

SNMP - Simple Network Management Protocol.  A protocol used to manage networks and routing.

SPX - Sequenced Packet Exchange, a connectioon-based IPX protocol.

Telnet - a TCP-based service that supports remote logins (usually to UNIX systems).(With telnet, you are sending your username and password over a network and they may be stolen by someone and used to break in.  Consider a VPN for privacy.)  Also, Routers are usually configured using Telnet.

TFTP - trivial file transfer protocol, a UDP-based file transfer protocol.  TFTP is a security risk because it involves no interaction with the user - it can occur without you knowing about it.

Trojan - a program or piece of executable code that is transmitted without the user's knowledge, often allowing outsiders to break into or control the system

Tunnel - encapsulating one protocol or data stream within another.  A Virtual Private Network (VPN) tunnels data by encrypting it and then encapsulating it within a protocol such as TCP (better) or UDP (worse).

Virus (software) - a piece of code that works without the knowledge of the recipient. It is transmitted inside other software, can duplicate itself, spread and damage your data and/or system.

VPN - Virtual Private Network. A secure private connection, usually through an untrusted network. You can link the LAN's of two offices through the Internet using a VPN, and systems in either office can access those in the other, as if they were on the same LAN. The route through the Internet is invisible. Hackers or snoopers on the Internet just see encrypted traffic and cannot get your private information.
(Another configuration of a VPN is "client/server", where computers, such as laptop PCs connect to a VPN server which gives access to a protected network. Home or mobile workers can connect to the office and have the same secure link and can access office systems.)

Winsock - a part of the Microsoft Windows operating systems that handles most network connections and some ICMP. It does not handle file or print shares.

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