Terms 11Terms 11

Definitions and QuestionsDefinitions and Questions

TCP/IPTCP/IP

Abbreviation of Abbreviation of Transmission Control Protocol,Transmission Control Protocol, and and pronounced as separate letters. TCP is one of the main pronounced as separate letters. TCP is one of the main protocolsprotocols in in TCP/IPTCP/IP networks. Whereas the networks. Whereas the IPIP protocol protocol deals only with deals only with packetspackets, TCP enables two , TCP enables two hostshosts to to establish a connection and exchange streams of data. establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which that packets will be delivered in the same order in which they were sent.they were sent.Internet Protocol - Internet Protocol - The The network layernetwork layer for the for the TCP/IPTCP/IP protocolprotocol suite widely used on suite widely used on EthernetEthernet networks. IP is a networks. IP is a connectionlessconnectionless, , best-effortbest-effort packet switchingpacket switching protocol. It protocol. It provides provides packetpacket routingrouting, , fragmentationfragmentation and re-assembly and re-assembly throughthe throughthe data link layerdata link layer..

IP AddressIP Address

An identifier for a computer or device on a TCP/IP network. An identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the Networks using the TCP/IP protocol route messages based on the IP address of the destination. The format of an IP address is a 32-bit IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. numeric address written as four numbers separated by periods. Each number can be zero to 255. For example, 1.160.10.240 could Each number can be zero to 255. For example, 1.160.10.240 could be an IP address. be an IP address. Within an isolated network, you can assign IP addresses at random Within an isolated network, you can assign IP addresses at random as long as each one is unique. However, connecting a private as long as each one is unique. However, connecting a private network to the Internet requires using registered IP addresses network to the Internet requires using registered IP addresses (called Internet addresses) to avoid duplicates. (called Internet addresses) to avoid duplicates. The four numbers in an IP address are used in different ways to The four numbers in an IP address are used in different ways to identify a particular network and a host on that network. identify a particular network and a host on that network.

UDPUDP

(User Datagram Protocol) (User Datagram Protocol) A protocol within the TCP/IP protocol suite that A protocol within the TCP/IP protocol suite that is used in place of TCP when a reliable delivery is used in place of TCP when a reliable delivery is not required. There is less processing of UDP is not required. There is less processing of UDP packets than there is for TCP. packets than there is for TCP. UDP is widely used for streaming audio and UDP is widely used for streaming audio and video, voice over IP (VoIP) and video, voice over IP (VoIP) and videoconferencing, because there is no time to videoconferencing, because there is no time to retransmit erroneous or dropped packets.retransmit erroneous or dropped packets.

TCP/IP Q/A TCP/IP Q/A

Q: What does the address 127.0.0.1 Q: What does the address 127.0.0.1 mean?mean?

A: 127.0.0.1 is a loopback network A: 127.0.0.1 is a loopback network connection. If you telnet, ftp, etc... to it you connection. If you telnet, ftp, etc... to it you are connected to your own machine. This are connected to your own machine. This is commonly used as a practical joke with is commonly used as a practical joke with people who are new to TCP/IP. It’s also people who are new to TCP/IP. It’s also called the “home” address.called the “home” address.

127.0.0.1127.0.0.1

Think GeekThink Geek

http://www.thinkgeek.com/tshirts/coder/5d6a/http://www.thinkgeek.com/tshirts/coder/5d6a/

Dynamic IPDynamic IP

A term used to describe how IP addresses A term used to describe how IP addresses are dynamically assigned to computers as are dynamically assigned to computers as and when needed. and when needed.

Unlike Static IP addresses, the IP address Unlike Static IP addresses, the IP address is temporary e.g. when you connect to is temporary e.g. when you connect to your ISP using a dial-up connection , you your ISP using a dial-up connection , you PC or router will be dynamically assigned PC or router will be dynamically assigned an IP address while you are on-line. an IP address while you are on-line.

Static IPStatic IP

Referred to as fixed IP address. Referred to as fixed IP address.

A static IP address is a number that is A static IP address is a number that is assigned to a computer by an Internet assigned to a computer by an Internet service provider (ISP) to be its permanent service provider (ISP) to be its permanent address on the internet.address on the internet.

Dynamic / Static IP Q/ADynamic / Static IP Q/A

Q: Who would typically have a static IP Q: Who would typically have a static IP address? Why?address? Why?

A: Large corporations tend to have static A: Large corporations tend to have static IPs for their servers. This allows their IPs for their servers. This allows their clients to consistently access these clients to consistently access these servers. servers.

DHCPDHCP-Short for -Short for DDynamic ynamic HHost ost CConfiguration onfiguration PProtocol,rotocol, a a protocolprotocol for assigning for assigning dynamicdynamic IP addressesIP addresses to devices on a to devices on a networknetwork. With dynamic addressing, a . With dynamic addressing, a device can have a different IP address every time it connects to the device can have a different IP address every time it connects to the network. In some systems, the device's IP address can even change while it network. In some systems, the device's IP address can even change while it is still connected. DHCP also supports a mix of static and dynamic IP is still connected. DHCP also supports a mix of static and dynamic IP addresses. addresses. A method of automatically assigning a TCP/IP address to a client. A DHCP A method of automatically assigning a TCP/IP address to a client. A DHCP server is used to dole out a TCP/IP address from a pool of TCP/IP server is used to dole out a TCP/IP address from a pool of TCP/IP addresses to a client that supports DHCP. When you connect to your ISP addresses to a client that supports DHCP. When you connect to your ISP over a modem or broadband you are typically assigned a dynamic (non-over a modem or broadband you are typically assigned a dynamic (non-static) TCP/IP address via DHCP. The big advantage to DHCP is that you static) TCP/IP address via DHCP. The big advantage to DHCP is that you don't need to manually assign a TCP/IP address to a client--the DHCP don't need to manually assign a TCP/IP address to a client--the DHCP server takes care of that. After an amount of time passes where the client server takes care of that. After an amount of time passes where the client does not contact the server, the server puts the TCP/IP address of the client does not contact the server, the server puts the TCP/IP address of the client back into the pool to be assigned to that client or any other client hat back into the pool to be assigned to that client or any other client hat requests a TCP/IP address. The disadvantage of DHCP for the DHCP client requests a TCP/IP address. The disadvantage of DHCP for the DHCP client is that the client is not guaranteed to have a particular TCP/IP address at is that the client is not guaranteed to have a particular TCP/IP address at any given time. For that you want a static IP address.any given time. For that you want a static IP address.

DNSDNS

Domain name servers, or DNS, are an incredibly important but Domain name servers, or DNS, are an incredibly important but completely hidden part of the Internet. The DNS system forms one completely hidden part of the Internet. The DNS system forms one of the largest and most active distributed databases on the planet. of the largest and most active distributed databases on the planet. Without DNS, the Internet would shut down very quickly.Without DNS, the Internet would shut down very quickly.This service maps TCP/IP numbers, such as 123.12.4.245, to a This service maps TCP/IP numbers, such as 123.12.4.245, to a more easily remembered name, such as www.geek.com. Thus, more easily remembered name, such as www.geek.com. Thus, when you type www.geek.com into your browser, it goes out to the when you type www.geek.com into your browser, it goes out to the DNS server specified by your ISP and asks for a matching TCP/IP DNS server specified by your ISP and asks for a matching TCP/IP address. If the browser finds a DNS entry for the name you typed in, address. If the browser finds a DNS entry for the name you typed in, you see the appropriate website. If not, it lets you know. Every you see the appropriate website. If not, it lets you know. Every domain name that is actually being used for a website has a domain name that is actually being used for a website has a corresponding TCP/IP address. When you set up a site you have corresponding TCP/IP address. When you set up a site you have your ISP add a DNS entry to its DNS servers (or manage it your ISP add a DNS entry to its DNS servers (or manage it yourself). This entry gets replicated across the Internet in a matter of yourself). This entry gets replicated across the Internet in a matter of hours, and, once fully replicated, you can reach your website from hours, and, once fully replicated, you can reach your website from any Internet connection.any Internet connection.

DHCP / DNS Q/ADHCP / DNS Q/A

Q: Does IU use DHCP for dorm Q: Does IU use DHCP for dorm connections?connections?A: Yes. If they didn’t, you would have to A: Yes. If they didn’t, you would have to call UITS up and request an IP address. call UITS up and request an IP address. Plus, if you took your computer off of the Plus, if you took your computer off of the network for a while and they accidentally network for a while and they accidentally gave ‘your’ IP address to someone else, gave ‘your’ IP address to someone else, you would have an IP conflict if you you would have an IP conflict if you plugged your machine back in.plugged your machine back in.

Denial of ServiceDenial of Service

An attack that is specifically designed to prevent the normal An attack that is specifically designed to prevent the normal functioning of a system, and thereby to prevent lawful access to that functioning of a system, and thereby to prevent lawful access to that system and its data by its authorized users. system and its data by its authorized users. On the Internet, a denial of service (DoS) attack is an incident in On the Internet, a denial of service (DoS) attack is an incident in which a user or organization is deprived of the services of a which a user or organization is deprived of the services of a resource they would normally expect to have. Typically, the loss of resource they would normally expect to have. Typically, the loss of service is the inability of a particular network service, such as e-service is the inability of a particular network service, such as e-mail, to be available or the temporary loss of all network connectivity mail, to be available or the temporary loss of all network connectivity and services. In the worst cases, for example, a Web site accessed and services. In the worst cases, for example, a Web site accessed by millions of people can occasionally be forced to temporarily by millions of people can occasionally be forced to temporarily cease operation. cease operation. Although usually intentional and malicious, a denial of service attack Although usually intentional and malicious, a denial of service attack can sometimes happen accidentally. A denial of service attack is a can sometimes happen accidentally. A denial of service attack is a type of security breach to a computer system that does not usually type of security breach to a computer system that does not usually result in the theft of information or other security loss. However, result in the theft of information or other security loss. However, these attacks can cost the target person or company a great deal of these attacks can cost the target person or company a great deal of time and money. time and money.

Honey PotHoney Pot

A honey pot is a computer system on the Internet that is A honey pot is a computer system on the Internet that is expressly set up to attract and "trap" people who attempt expressly set up to attract and "trap" people who attempt to penetrate other people's computer systems. To set up to penetrate other people's computer systems. To set up a honey pot, it is recommended that you: a honey pot, it is recommended that you:

Install the Install the operating systemoperating system without without patchpatches installed and using es installed and using typical defaults and options typical defaults and options

Make sure that there is no data on the system that cannot safely Make sure that there is no data on the system that cannot safely be destroyed be destroyed

Add an application that is designed to record the activities of the Add an application that is designed to record the activities of the invader invader

Maintaining a honey pot is said to require a considerable Maintaining a honey pot is said to require a considerable amount of attention and may offer as its highest value amount of attention and may offer as its highest value nothing more than a learning experience (that is, you nothing more than a learning experience (that is, you may not catch any crackers). may not catch any crackers).

War DialingWar Dialing

A war dialer is a computer program used to identify the A war dialer is a computer program used to identify the phone numbers that can successfully make a connection phone numbers that can successfully make a connection with a computer modem. The program automatically with a computer modem. The program automatically dials a defined range of phone numbers and logs and dials a defined range of phone numbers and logs and enters in a database those numbers that successfully enters in a database those numbers that successfully connect to the modem. Some programs can also identify connect to the modem. Some programs can also identify the particular operating system running in the computer the particular operating system running in the computer and may also conduct automated penetration testing. In and may also conduct automated penetration testing. In such cases, the war dialer runs through a predetermined such cases, the war dialer runs through a predetermined list of common user names and passwords in an attempt list of common user names and passwords in an attempt to gain access to the system. to gain access to the system. An identical technique was sometimes used to get the An identical technique was sometimes used to get the first call for prizes in radio "call-in" shows, thus leading to first call for prizes in radio "call-in" shows, thus leading to the adoption of random "fifth caller," "secenteenth caller" the adoption of random "fifth caller," "secenteenth caller" etc. by radio stations to circumvent this practice.  etc. by radio stations to circumvent this practice.  

WiFiWiFi

Short for ‘wireless fidelity’. A term for certain Short for ‘wireless fidelity’. A term for certain types of wireless local area networks (WLAN) types of wireless local area networks (WLAN) that use specifications conforming to IEEE that use specifications conforming to IEEE 802.11. 802.11. WiFi has gained acceptance in many WiFi has gained acceptance in many environments as an alternative to a wired LAN. environments as an alternative to a wired LAN. Many airports, hotels, and other services offer Many airports, hotels, and other services offer public access to WiFi networks so people can public access to WiFi networks so people can log onto the Internet and receive emails on the log onto the Internet and receive emails on the move. move. These locations are known as hotspots.These locations are known as hotspots.

War ChalkingWar ChalkingWarchalking is the practice of marking a series of symbols on Warchalking is the practice of marking a series of symbols on sidewalks and walls to indicate nearby wireless access. That way, sidewalks and walls to indicate nearby wireless access. That way, other computer users can pop open their laptops and connect to the other computer users can pop open their laptops and connect to the Internet wirelessly.Internet wirelessly.As the Warchalking web site states, this kind of language was first As the Warchalking web site states, this kind of language was first utilized by hobos during the Great Depression to communicate with utilized by hobos during the Great Depression to communicate with each other for various purposes, mostly to find safe harbor. each other for various purposes, mostly to find safe harbor. Warchalking itself capitalizes on this idea. Wireless users help other Warchalking itself capitalizes on this idea. Wireless users help other wireless users by communicating about nearby access pointswireless users by communicating about nearby access pointsCreator Matt Jones began by posting three possible war chalking Creator Matt Jones began by posting three possible war chalking symbols on his blog. Two semi-circles back-to-back would indicate symbols on his blog. Two semi-circles back-to-back would indicate an open an open nodenode, a circle would indicate the presence of a closed , a circle would indicate the presence of a closed node, and a circle with the letter "W" inside it would indicate a node, and a circle with the letter "W" inside it would indicate a WEPWEP node. Ideally, each symbol would be chalked with a corresponding node. Ideally, each symbol would be chalked with a corresponding SSIDSSID next to it which would act as a password to the node. next to it which would act as a password to the node.

War ChalkingWar Chalking

War DrivingWar Driving

AA computer cracking technique that computer cracking technique that involves driving through a neighborhood involves driving through a neighborhood with a with a wireless-enabled notebook wireless-enabled notebook computer and mapping houses and computer and mapping houses and businesses that have wireless access businesses that have wireless access points. points.

War Q/AWar Q/A

Q: Other than people trying to break into Q: Other than people trying to break into computers, who might use a wardialer or computers, who might use a wardialer or wardialer-like system?wardialer-like system?A: Telemarketers use wardialer-like A: Telemarketers use wardialer-like systems to call hundreds of numbers at systems to call hundreds of numbers at once, and then transfer numbers that once, and then transfer numbers that picked up to salesmen. In this case, picked up to salesmen. In this case, they’re actually looking for numbers –not- they’re actually looking for numbers –not- connected to modems or faxes.connected to modems or faxes.

Short QuizShort Quiz

Please get out a blank sheet of paper and Please get out a blank sheet of paper and put your name and the date on it.put your name and the date on it.

Short QuizShort Quiz

1.1. Define “HTML”.Define “HTML”.2.2. Define “DRM”.Define “DRM”.3.3. Analog signals are composed of discrete Analog signals are composed of discrete

1s and 0s – T/F?1s and 0s – T/F?4.4. Your intranet and extranet are often Your intranet and extranet are often

separated by a _______ designed to separated by a _______ designed to keep out intruders.keep out intruders.

5.5. How many signals are needed for GPS How many signals are needed for GPS to precisely pinpoint your location?to precisely pinpoint your location?

Short QuizShort Quiz

1.1. Hyper Text Markup LanguageHyper Text Markup Language

2.2. Digital Rights ManagementDigital Rights Management

3.3. FF

4.4. FirewallFirewall

5.5. 33