Common Ports

Question 1

FTP

Answer 1

21 - TCP

File Transfer Protocol is used to transfer files from host to host

Question 2

SSH

Answer 2

22 - TCP/UDP

Secure Shell is used to remotely administer network devices and systems.

Question 3

SCP

Answer 3

22 - TCP/UDP

SCP is used for secure copy

Question 4

SFTP

Answer 4

22 - TCP/UDP

SFTP for secure FTP

Question 5

Telnet

Answer 5

23 - TCP/UDP

Unencrypted method to remotely administer network devices (Should not be used)

Question 6

SMTP

Answer 6

25 - TCP

Simple Mail Transfer Protocol is used to send email over the internet

Question 7

DNS

Answer 7

53 - TCP/UDP

Domain Name Service is used to resolve hostnames to IPs and IPs to hostnames

Question 8

TFTP

Answer 8

69 - UDP

Trivial FTP is used as a simplified version of FTP to put a file on a remote host, or get a file from a remote host

Question 9

HTTP

Answer 9

80 - TCP

Hyper Text Transfer Protocol is used to transmit web page data to a client for unsecured web browsing

Question 10

Kerberos

Answer 10

88 - TCP/UDP

Used for network authentication using a system of tickets within a Windows domain

Question 11

POP3

Answer 11

110 - TCP

Post Office Protocol v3 is used to receive email from a mail server

Question 12

NNTP

Answer 12

119 - TCP

Network News Transfer Protocol is used to transport Usenet articles

Question 13

RPC/DCOM-scm

Answer 13

135 - TCP/UDP
Remote Procedure Call is used to locate DCOM ports to request a service from a program on another computer on the network

Question 14

NetBIOS

Answer 14

137-139 - TCP/UDP

NetBIOS is used to conduct name querying, sending of data, and other functions over a NetBIOS connection

Question 15

IMAP

Answer 15

143 - TCP

Internet Message Access Protocol is used to receive email from a mail server with more features than POP3

Question 16

SNMP

Answer 16

161 - UDP

Simple Network Management Protocol is used to remotely monitor network devices

Question 17

SNMPTRAP

Answer 17

162 - TCP/UDP

Used to send Trap and InformRequests to the SNMP Manager on a network

Question 18

LDAP

Answer 18

389 - TCP/UDP

Lightweight Directory Access Protocol is used to maintain directories of users and other objects

Question 19

HTTPS

Answer 19

443 - TCP

Hyper Text Transfer Protocol Secure is used to transmit web page data to a client over an SSL/TLS encrypted connection

Question 20

SMB

Answer 20

445 - TCP

Server Message Block is used to provide shared access to files and other resources on a network

Question 21

SMTP with SSL/TLS

Answer 21

465/587 - TCP

Simple Mail Transfer Protocol used to send email over the internet with an SSL and TLS secured connection

Question 22

Syslog

Answer 22

514 - UDP

Syslog is used to conduct computer message logging, especially for routers and firewall logs

Question 23

LDAP over SSL/TLS

Answer 23

636 - TCP/UDP

LDAP is used to maintain directories of users and other objects over an encrypted SSL/TLS connection

Question 24

iSCSI

Answer 24

860 - TCP

iSCSI is used for linking data storage facilities over IP

Question 25

FTPS

Answer 25

989/990 - TCP | File Transfer Protocol Secure is used to transfer files from host to host over an encrypted connection

Question 26

IMAP4 with SSL/TLS

Answer 26

993 - TCP | Internet Message Access Protocol is used to receive email from a mail server over an SSL/TLS-encrypted connection

Question 27

POP3 (SSL/TLS)

Answer 27

995 - TCP | Post Office Protocol v3 is used to receive email from a mail server using an SSL/TLS-encrypted connection

Question 28

Ms-SQL-s

Answer 28

1433 - TCP | Microsoft SQL server is used to receive SQL database queries from clients

Question 29

RADIUS (alternative)

Answer 29

1645/1646 - UDP | Remote Authentication Dial-In User Service is used for authentication and authorization (1645) and accounting (1646)

Question 30

L2TP

Answer 30

1701 - UDP | Layer 2 Tunnel Protocol is used as an underlying VPN protocol but has no inherent security

Question 31

PPTP

Answer 31

1723 - TCP/UDP | Point-to-Point Tunneling Protocol is an underlying VPN protocol with built-in security

Question 32

RADIUS

Answer 32

1812/1813 - UDP | Remote Authentication Dial-In User Service is used for authentication and authorization (1812) and accounting (1813)

Question 33

FCIP

Answer 33

3225 - TCP/UDP | Fibre Channel IP is used to encapsulate Fibre Channel frames within TCP/IP packets

Question 34

iSCSI Target

Answer 34

3260 - TCP | iSCSI Target is as the listening port for iSCSI-targeted devices when linking data storage facilities over IP

Question 35

RDP

Answer 35

3389 - TCP/UDP | Remote Desktop Protocol is used to remotely view and control other Windows systems via a Graphical User Interface

Question 36

Diameter

Answer 36

3868 - TCP | A more advanced AAA protocol that is a replacement for RADIUS

Question 37

Syslog over TLS

Answer 37

6514 - TCP It is used to conduct computer message logging, especially for routers and firewall logs, over a TLS-encrypted connection