Class 3 - Introduction To TCP/IP

Question 1

What is Telnet and what does it do?

Answer 1

-One of the first protocols used on ARPAnet

-Creates a virtual terminal (TTY) on the host computer

-No encryption - even passwords sent in clear text!

Question 2

What is SSH and what does it do?

Answer 2

Secure Shell

-Similar to telnet

-All connections are encrypted

-Can be used to tunnel other protocols (useful for protocols that aren’t encrypted)

Question 3

What is FTP and what does it do?

Answer 3

File Transfer Protocol

-Allows for viewing and transferring of files to and from a server

-Data is not encrypted

-Unusual protocol - uses 2 separate ports

Question 4

What is TFTP and what does it do?

Answer 4

Trivial File Transfer Protocol

-Simple, stripped-down version of FTP

-No security

-No directory listings

-Client needs to know the name of the file

-Used extensively by Cisco for system recovery

Question 5

What is SNMP and what does it do?

Answer 5

Simple Network Management Protocol

-Used for collecting and changing configuration and accounting data in a network

-Polls machines to ask for certain pieces of data, such as disk space, temperature, etc.

-Responds to messages sent directly from machines (called Traps) - usually because of an unusual event

Question 6

What is HTTP and what does it do?

Answer 6

Hyper Text Transport Protocol

-The protocol responsible for transferring and displaying web pages

-Your browser can understand what you need when you enter a Uniform Resource Locator (URL), which we usually refer to as a web address, e.g. http://www.lammle.com/forum and http://www.lammle.com/blog.

Question 7

What is NTP and what does it do?

Answer 7

Network Time Protocol

-Used to synchronise computer clocks

Question 8

What is DNS and what does it do?

Answer 8

Domain Name Service

-Resolves hostnames (www.lammle.com) in to IP addresses (184.172.53.52)

-Distributed protocol - no single server has all of the data

-Requests are handed from server to server until the answer is obtained

Question 9

What is ICMP and what does it do?

Answer 9

Internet Control Message Protocol

-Used for low-level network messages, for example “Destination unreachable”, “Ping”, “Time to live exceeded”

Question 10

What is ARP and what does it do?

Answer 10

Address Resolution Protocol

-ARP resolves IP addresses to Ethernet (MAC) addresses.