Terms 11

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Terms 11

• Definitions and Questions

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TCP/IP

• Abbreviation of Transmission Control Protocol,
  and pronounced as separate letters. TCP is one of
  the main protocols in TCP/IP networks. Whereas
  the IP protocol deals only with packets, TCP
  enables two hosts to establish a connection and
  exchange streams of data. TCP guarantees delivery
  of data and also guarantees that packets will be
  delivered in the same order in which they were
  sent.
• Internet Protocol - The network layer for the
  TCP/IP protocol suite widely used on Ethernet
  networks. IP is a connectionless, best-effort
  packet switching protocol. It provides packet
  routing, fragmentation and re-assembly throughthe
  data link layer.

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IP Address

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

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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. There is less processing of UDP
  packets than there is for TCP.
• UDP is widely used for streaming audio and video,
  voice over IP (VoIP) and videoconferencing,
  because there is no time to retransmit erroneous
  or dropped packets.

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TCP/IP Q/A

• Q What does the address 127.0.0.1 mean?
• A 127.0.0.1 is a loopback network connection. If
  you telnet, ftp, etc... to it you are connected
  to your own machine. This is commonly used as a
  practical joke with people who are new to TCP/IP.
  Its also called the home address.

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127.0.0.1

• Think Geek
• http//www.thinkgeek.com/tshirts/coder/5d6a/

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Dynamic IP

• A term used to describe how IP addresses are
  dynamically assigned to computers as and when
  needed.
• Unlike Static IP addresses, the IP address is
  temporary e.g. when you connect to your ISP using
  a dial-up connection , you PC or router will be
  dynamically assigned an IP address while you are
  on-line.

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Static IP

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

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Dynamic / Static IP Q/A

• Q Who would typically have a static IP address?
  Why?
• A Large corporations tend to have static IPs for
  their servers. This allows their clients to
  consistently access these servers.

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DHCP

• -Short for Dynamic Host Configuration Protocol, a
  protocol for assigning dynamic IP addresses to
  devices on a network. With dynamic addressing, a
  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 is
  still connected. DHCP also supports a mix of
  static and dynamic IP addresses.
• 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
  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-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 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 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 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.

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DNS

• Domain name servers, or DNS, are an incredibly
  important but completely hidden part of the
  Internet. The DNS system forms one of the largest
  and most active distributed databases on the
  planet. Without DNS, the Internet would shut down
  very quickly.
• This service maps TCP/IP numbers, such as
  123.12.4.245, to a more easily remembered name,
  such as www.geek.com. Thus, 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 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 domain name that is actually being used for
  a website has a 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
  yourself). This entry gets replicated across the
  Internet in a matter of hours, and, once fully
  replicated, you can reach your website from any
  Internet connection.

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DHCP / DNS Q/A

• Q Does IU use DHCP for dorm connections?
• A Yes. If they didnt, you would have to call
  UITS up and request an IP address. Plus, if you
  took your computer off of the network for a while
  and they accidentally gave your IP address to
  someone else, you would have an IP conflict if
  you plugged your machine back in.

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Denial of Service

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

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Honey Pot

• A honey pot is a computer system on the Internet
  that is expressly set up to attract and "trap"
  people who attempt to penetrate other people's
  computer systems. To set up a honey pot, it is
  recommended that you
• Install the operating system without patches
  installed and using typical defaults and options
• Make sure that there is no data on the system
  that cannot safely be destroyed
• Add an application that is designed to record the
  activities of the invader
• Maintaining a honey pot is said to require a
  considerable amount of attention and may offer as
  its highest value nothing more than a learning
  experience (that is, you may not catch any
  crackers).

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War Dialing

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

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WiFi

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

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War Chalking

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

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War Chalking
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War Driving

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

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War Q/A

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

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Short Quiz

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

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Short Quiz

1. Define HTML.
2. Define DRM.
3. Analog signals are composed of discrete 1s and 0s
   T/F?
4. Your intranet and extranet are often separated by
   a _______ designed to keep out intruders.
5. How many signals are needed for GPS to precisely
   pinpoint your location?

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Short Quiz

1. Hyper Text Markup Language
2. Digital Rights Management
3. F
4. Firewall
5. 3