Networking - Ports and Port Numbers+Protocols

Question 1

What is a port?

Answer 1

A virtual place where network connections start and end. They divert network traffic to the application/s that deal with it.

Question 2

Why are well known port numbers standardised (kept the same generally)?

It is important to know the most common port numbers, the protocols they

Answer 2

To allow server and client to communicate and the applications on both sides that need that data to get it.

To allow the data through device firewalls - the port number is a major part of whether a firewall decides to let data through or not.

Question 3

What is FTP protocol for? What ports does it use?

Answer 3

File Transfer Protocol is used for data transfer between systems/devices.

It uses port tcp/20 - for the data transfer (20). 20 data transfer
And it uses port tcp/21 - to control the data transfer (21 - control of transfer).

FTP - Twenty P
Twenty Plus
20 (transfer) + 21 (control)

Question 4

What protocol is port 80 known for?

Answer 4

It is used for HTTP (web) requests between client and server.

HTTP - 80p doesn’t get you much webs server securiTy.

Hyper Text Transfer Protocol - Port tcp/80
HateyP 80p HTTP

Question 5

What is SSH and what port is it on?

Answer 5

Secure SHell is a way to send data securely over an unsecure network by using ENCRYPTION and AUTHENTICATION. Port tcp/22

22H - SSH - SSH Port 22. Shh port 22. 2xS - encrypted snake connectors.

Enigma Turtle - encrypted 22H SSH

Feeling secure in my SSHell. My 2x2 shell

Question 6

What does it mean when it is said that a communication/connection between network devices is made “in the clear”?

Answer 6

It means that the connection is not encrypted.
Therefore if a data packet is intercepted in transit across the network the data is readable.

An example of a protocol that makes unencrypted/in the clear connections is TELNET port 23 (2x3 letter words TELecommunication NETwork).

TELl the NET your password by using telnet 23 unencrypted protocol from port 23.

Question 7

On which port does sending Emails thrive?

Answer 7

Port 25 is where sending emails thrive! SMTP

Sending Mail Thrives Port 25

Server to server email transfer protocol.

Simple Mail Transfer Protocol - 25

Question 8

Which port used for retrieving emails is more secure IMAP4 or POP3?

Answer 8

IMAP4 on port 143 is more secure and provides more in depth email management than POP3 (110).

IMAP4 lets you access emails from multiple devices POP3 does not.

I love you IMAP4 (1 letter word 4 letter word 3 letter word)

I 4 3
IMAP4

P0P3
110

Question 9

What port number is associated with POP3 and what is POP3 for?

Answer 9

Port 110 and POP3 - Post Office Protocol v3 - is used for receiving/retrieving emails from a mail server.

It can only be used from one device at a time unlike IMAP4 - I love You IMAP4 port tcp 143

Question 10

What port is HTTPS and how does it differ from HTTP?

Answer 10

HTTPS - HyperText Transfer Protocol Secure runs on port 443. Web server security on port 443. AA3 -> 443 -> access web securily.

It uses encryption to secure web server data being transferred whereas HTTP (the original web server protocol) does not. HTTP - port eighTEA 80

Question 11

What does NetBIOS stand for? And what ports does it use to find devices on the network and establish a session to transfer the data?

Answer 11

NetBIOS - Network Basic Input/Output System is an OLD way to do file sharing on Windows systems. Such as sending files to a printer or other device on the Network. The new way is via port 445 NetBIOS-less.

NetBIOS over TCP/IP uses two ports in order:
1. udp 137 - name services - used to find devices on the network
2. tcp 139 - session service - used to establish a session with the device and transfer data to it (encrypted as it’s tcp)

NetBIOS 137 to 139 is old Windows file sharing time! udp (device name find) -> tcp (establish session and transfer data) -> print

Question 12

Which mail retrieval protocol allows you to synchronize your emails across multiple devices and which port does it run on?

Answer 12

IMAP4 - Internet Message Access Protocol v4 lets you access your mailbox from multiple devices and provides a lot more mail management options than Post Office Protocol v3 (P0P3). IMAP4 - I love you runs on port 143 (word letter length).

Question 14

There are 3 versions of SNMP what advantage does version 3 provide over the previous versions. What port/s does SNMP use?

Answer 14

Simple Mail Transfer Protocol version 3 (v3) uses encryption and authentication to keep the monitored network device data secure which the previous/old versions of SNMP did not.

SNMP uses ports udp/161 (queries/data requests) and udp/162 (traps/alerts).

Question 15

What protocol does Microsoft Active Directory (example of a Network Directory) use to store and retrieve information?

What port does the protocol use to do this?

Answer 15

LDAP - Lightweight Directory Access Protocol that runs on tcp/389

389 it’s active directory time!

LDAP is used to store and retrieve information within a network directory (such as Active Directory).

Question 16

What port does LDAP run on and what does it stand for and do?

Answer 16

LDAP runs on port 389 and stands for Lightweight-Directory-Access-Protocol and is used to fetch and push data (retrieve and store) to a Network Directory (such as the Microsoft Active Directory).

389 its active directory accessing time.

Question 17

What is the biggest commonly used TCP port number and what protocol runs on it? And what does that protocol do?

Answer 17

3389 is the biggest commonly used port number and it is used for RDP - Remote Desktop Protocol.

RDP is used to access/share desktop or a single application on a desktop remotely (through a network connection).

Question 18

What port would you use to access a desktop on your network remotely?

Answer 18

Port 3389 (THE BIG RDP). Remote Desktop Protocol.

Question 19

What protocol runs on port tcp/995?

Answer 19

POP3S - POP3 Secure - Post Office Protocol v3 Secure - used for downloading mail to local mail client. (Deletes mail from server when downloaded (can be configured not to))

POP3 - tcp/110
POP3S - tcp/995

Question 20

What port does IMAP-S use?

Answer 20

IMAPS - Internet Messaging Access Protocol Secure - uses tcp/993

Question 21

What port does SMTP with AUTHENTICATION use?

Answer 21

TCP/587
587 with AUTH
25 without AUTH

Question 22

The Service Location Protocol (SLP) allows devices to locate/discover services (like printers) on their LAN without prior configuration. What port does it run on?

Answer 22

udp/427 is the port that SLP (Server Location Protocol) uses.

Question 23

What is the 802.3 IEEE standard used for?

Answer 23

Power over Ethernet standard/protocols. 802.3

Question 24

Which of the three 802.3 standards has the lowest power output? (15.4W)

Answer 24

802.3af provides 15.4W power and is the weakest (AF) PoE standard of the 3.

Question 25

What is the highest power output provided over Ethernet (W) and which 802.3 standard supports it?

Answer 25

60W is supported by 802.3bt standard (double the power output of 802.3at)

Question 26

What does the Syslog protocol do in a network?

Answer 26

Syslog protocol is a standard used by computer systems in a network to send EVENT LOGS to a centralised storage server which can then be analysed and used for monitoring, reporting purposes.