Port numbers

Question 1

23

Answer 1

Telnet -

1. Telecommunication network
2. Login to devices remotely
3. Console access
4. In-the-clear communcation (NO ENCRYPTION)”

Question 2

22

Answer 2

SSH (Secure shell) -

Like telnet, but encrypted. Designed to transmit data through a remote connection.

Question 3

53

Answer 3

DNS (Domain Name System) -

“Converts names to IP addressses
Very critical resources”

Question 4

25

Answer 4

SMTP (Simple Mail Transfer Protocol) -

“Server to server email transfer - NOT encrypted.
Also used to send mail from a device to a mail server.
Commonly configured on mobile devices and email”

Question 5

587

Answer 5

SMTP (Simple Mail Transfer Protocol) - using TLS encryption

Question 6

110

Answer 6

POP3 (Post Office Protocol Ver 3) -

“Basic mail transfer functionality.
Receive email from email server.
Only one-way communication.
NOT encrypted”

Question 7

995

Answer 7

POP3 over TLS (Encrypted)

Question 8

143

Answer 8

IMAP (Internet Message Access Protocol v4) -

Includes mgmt of email inbox from multiple clients.
Provides 2-way communication unlike POP.
IN THE CLEAR.

Question 9

993

Answer 9

IMAP (Internet Message Access Protocol v4) -

Includes mgmt of email inbox from multiple clients.
Provides 2-way communication unlike POP.
ENCRYPTED

Question 10

22

Answer 10

SSH FTP - Secure File Transfer Protocol -

Provides file system functionality
Resuming uninterrupted transfers
Directory listings
Remote file removal
A completely separate protocol from FTP (it is not compliant with FTP servers) that uses SSH to encrypt file transfers.

Question 11

20

Answer 11

FTP (File transfer protocol) -

Active Mode data - actually transferring a file.
Transfers files between systems.
Authenticates with username and password.
Full-featured functionality (list, add, delete, etc.)

Question 12

21

Answer 12

FTP (File transfer protocol) -

Control - tells computer which file to send.

Question 13

69

Answer 13

TFTP - Trivial FTP -

Very simple file transfer app.
No authentication
Read and writes files

Question 14

67, 68

Answer 14

DHCP (Dynamic Host Configuration Protocol)

Requires a DHCP server.
1. Dynamic/pooled - IPs assigned in real time from a pool. Each client given a lease and must renew.
2. DHCP reservation - addresses assigned by MAC address.
This network management protocol is used to assign local IP addresses to devices on a network. It is used to create multiple private IP addresses from one public IPv4 address.

Question 15

80

Answer 15

HTTP (Hypertext transfer protocol) -

Protocol used for websites and most internet traffic. NO ENCRYPTION

Question 16

443

Answer 16

HTTP over TLS

Question 17

161

Answer 17

SNMP (Simple Network Management Protocol) -
Gather stats from network devices.

Question 18

162

Answer 18

SNMP traps -

Alerts and notifications from network devices. (If anything bad happens, let us know.)

Question 19

514

Answer 19

Syslog -

Usually a central log connector (integrated into a SIEM)

Question 20

389

Answer 20

LDAP (Lightweight Directory Access Protocol) -

Store and retrieve info in a network directory (user info, passwords, etc).
Used to manage and communicate with directories.

Question 21

636

Answer 21

LDAPS (LDAP Secure) - “LDAP” over TLS -

Store and retrieve info in a network directory (user info, passwords, etc).
Used to manage and communicate with directories.

Question 22

49

Answer 22

TACACS+

Cisco proprietary protocol used for authentication, authorization, and accounting (AAA) services

Question 23

88

Answer 23

Kerberos -

Network authentication protocol that allows for communication over a non-secure network.

Question 24

989/990

Answer 24

File Transfer Protocol Secure (FTPS) -

FTPS uses TLS for encryption. IT can run on ports 20/21, but is sometimes allocated to ports 989/990.

Question 25

1812, 1813

Answer 25

Remote Authentication Dial-In User Service (RADIUS) -

Used to provide AAA for network devices. like TACACS+ or Kerberos

Question 26

3868

Answer 26

Diameter - developed as an upgrade to RADIUS.

Question 27

5004

Answer 27

Secure Real Time Protocol (SRTP) -

SRTP replaced RTP and is a protocol used to stream audio and video communication using UDP.

Question 28

1701

Answer 28

Layer 5 Session Layer.

Layer 2 Tunneling Protocol (L2TP) -

Used to create point to point connections, like VPNs over a UDP connection. Needs IPSec for encryption. Designed as an extension to (Point to Point Tunneling Protocol) PPTP. Operates at the data link layer but encapsulates packets at the session layer.

Question 29

TCP (Transmission Control Protocol)

Answer 29

Layer 4 - Transport

One of two main protocols of the Internet Protocol (IP) suite used to transmit data over an IP network. TCP provides error checking to ensure packets are not lost in transit.

Question 30

UDP (User Datagram Protocol)

Answer 30

Layer 4 - Transport

The second main protocol in the IP suite that transmits datagrams in a best effort method. UDP does not include error checking.

Question 31

1723

Answer 31

Layer 4 - Transport

Point to Point Tunneling Protocol (PPTP) -

Based on PPP. Deprecated protocol for VPNs.

Question 32

3389

Answer 32

Layer 4 - Transport

RDP (Remote Desktop Protocol) -

Remote Desktop Services - Windows proprietary protocol that provides a remote connection between two computers.