05 - Ports and Client Ports

 1. On a TCP/IP network every device must have an IP address. The IP address identifies the device e.g. computer.



 2. A computer can run multiple applications and/or services. Just as the IP address identifies the computer, The network port ___________________________

  identifies the cable to be used for the internet connection

  identifies the individuals that are connected to the ISP

  identifies the application or service running on the computer.

  identifies the different internet browsers that are running on the machine

 3. Read the following alternative definition of ports and fill in the blanks.
A port is a ___________________________________________ a transaction over a 
network by specifying both the host, and the service. They are necessary to 
differentiate between many different IP services, such as web service (HTTP),
 mail service (SMTP), and file transfer (FTP).

  physical plug that authorises

  number used to uniquely identify

  string sequence used to divide

  ASCIi code used to identify

 4. The use of ports allow computers/devices to _________________________________

  None of the above

  divide up packets and send them through a router

  send datagrams and packets wirelessly without protocols

  run multiple services/applications.

 5. The diagram below shows a computer to computer connection and identifies the IP addresses and ports.



 6. The ports referred to in the context of TCP/IP are …..

  None of the above

  cabled ports (that are actually cables)

  physical ports

  logical ports (not tangible hardware ports)

 7. To use an analogy, if you lived in a house on a street, the IP address corresponds to the ________________

  house number + street address

  street address

  post code

  house number

 8. In an analogy of houses on a street, all houses share the same street addres (IP ADDRESS). The port number in this case would correspond to the ______________

  post code

  house number + street address

  street address

  house number

 9. A port number uses ____________ and can have a value from 0 to 65535 decimal. Port numbers are divided into ranges.

  8 bits

  256 bits

  16 bits

  24 bits

 10. Port numbers 0 - 1023 are usually well known ports. These are allocated to server services b the Internet Assigned Numbers Authority (IANA). E.g. Web servers normally use ______________ and SMTP use _____________.

  port 8 / port 8080

  port 25 / port 80

  port 80 / port 25

  port 100 / port 256

 11. The 'third' category ports 49152 - 65535 are used by _________________and unlike 'registered ports/semi reserved) they are also called ephemeral ports


  None of the above

  server services

  client programs

 12. The client port that a server request is returned to is usually a temporary and arbitary port number. This is a ________________________

  cable-protection method

  security measure to ensure that hackers don't know which ports are open on a client machine

  unblocking technique, to ensure that the network is accessible by all users

  web-browsing facility, which allows efficient connectivity to the internet

 13. The default port number for HTTP is 80 - and it is used to identify packets for transfer to the web server



 14. Port numbers are never used in providing firewall security as they are not capable of stipulating the destination of information on a network.



 15. Other well known port numbers include 20 and 21 for FTP (Data transfer and Command control), 22 for Secure Shell, 23 for Telnet and 443 for ______________


  HTTP secure (HTTPS)

  Domain Name System (DNS)

  Network Time Protocol (NTP)