Common Ports

Question 1

FTP

Answer 1

TCP
20/21 (passive)
20 (active)

-File transfer

Question 2

SSH (Secure Shell)

Answer 2

TCP
22
Secure remote control

Question 3

Telnet

Answer 3

TCP
23
Remote control (unsecure/unencrypted)

Question 4

SMTP (Simple Mail Transfer Protocol)

Answer 4

TCP
25
Sending e-mail

Question 5

DNS (Domain Name System)

Answer 5

UDP
53
Naming = Linking IP with domain name

Question 6

DHCP

Answer 6

UDP
67 (server)
68 (client)
Assigns IP info

Question 7

TFTP (Trivial File Transfer Protocol)

Answer 7

UDP
69
File transfer - UDP = connectionless => not reliable or secure

Question 8

HTTP

Answer 8

TCP
80
The Web (unsecure)

Question 9

POP3 (Post Office Protocol version 3)

Answer 9

TCP
110
E-mail retrieval

Question 10

NTP/SNTP (Network Time Protocol/Simple Network Time Protocol)

Answer 10

UDP
123
Time synchronization

Question 11

IMAP4 (Internet Message Access Protocol version 4)

Answer 11

TCP
143
E-mail retrieval (better than POP3)

Question 12

HTTPS

Answer 12

TCP
443
The Web (secure)

Question 13

SQL Server

Answer 13

TCP
1433
Database server
* uses many other ports with different but registered as 1433 with IANA)

Question 14

SQLnet

Answer 14

TCP
1521
Database server

Question 15

MySQL

Answer 15

TCP
3306
Database server

Question 16

Range of well-known ports

Answer 16

0 - 1023

Question 17

Range of registered ports

Answer 17

1024 - 49151

Question 18

Range of Dynamic/Ephemeral/private ports

Answer 18

49152 - 65535