Ports and protocols

40 Questions

What is the primary function of the Session Initiation Protocol (SIP)?

Session setup, maintenance, and teardown

Which protocol uses TCP port 1720?

H.323

Which of the following protocols is commonly used for file sharing?

SMB

What is the typical port number used by Microsoft SQL Server?

1433

Which SQL Server uses TCP port 1521?

Oracle SQL Server

What is the typical port number used by MySQL?

3306

What is the purpose of the Microsoft SQL Server Management Studio (SMS)?

To manage database servers

Why are flashcards recommended for memorizing protocols and ports?

To help memorize and associate protocols with their respective ports

What protocol is used to send mail to an email server?

SMTP

What port is used by SMTP to send email to an email server?

TCP Port 25

Which protocol is used to resolve a domain name into an IP address?

DNS

What protocol is used to transfer files without requiring user credentials?

TFTP

Which protocol is used to provide IP address information to a device on a network?

DHCP

What protocol is used to exchange information with an unsecured web server?

HTTP

What protocol is used to retrieve email from an email server?

POP3

What protocol is used to secure the transmission of email using SSL or TLS?

SMTP over SSL/TLS

What is the primary purpose of using a well-known port number when connecting to a web server?

To enable communication between the client and server

What is the range of well-known port numbers?

0-1023

What is the purpose of the ephemeral port number in the IP packet header?

To specify the source port number for the client

What transport layer protocol is used when connecting to a traditional web server?

TCP

What is the destination port number used when connecting to a traditional web server?

What is the term for the source port number used by the client when connecting to a web server?

All of the above

What is the range of registered port numbers?

1024-49151

What is the purpose of the source IP address in the IP packet header?

To specify the client's IP address

What is the primary purpose of registering a protocol with the Internet Assigned Numbers Authority (IANA)?

To avoid overlapping port numbers between different vendors and organizations

What is the range of ephemeral ports, also known as dynamic or private ports?

49152-65535

Which protocol is used to securely connect to a remote system and protect traffic over an untrusted network?

SSH

What is the difference between SFTP and FTPS?

SFTP is secure FTP, while FTPS is FTP over SSL/TLS

Which protocol uses TCP port 23 and provides a plain text connection with a remote device?

Telnet

What is the primary purpose of using Secure Shell (SSH) instead of Telnet?

To securely connect to a remote system and protect traffic over an untrusted network

What is the range of registered ports?

1024-49151

Which protocol is used for email and uses TCP port 25 by default?

SMTP

Which protocol uses UDP port 123 to communicate authoritative time to network devices?

NTP

What is the primary purpose of the iMap protocol?

To view emails on the email server without removing them

Which protocol is commonly used in large enterprise environments for directory services?

Ldap

Which protocol uses TCP port 993 and is commonly used to secure email communications?

iMap

What is the primary purpose of the SNMp protocol?

To manage network devices and query them for information

Which port is used by the RDP protocol?

3389

What is the term for a communication initiated from an SNMp agent to a server?

Trap

Which protocol is commonly used to secure Ldap communications?

Both A and B

Study Notes

Network Communication Basics

A common network activity is a client (e.g., laptop) communicating with a web server, which requires knowing the web server's IP address and the well-known port number for web services (TCP port 80).
The client's IP address is the source IP address, and the web server's IP address is the destination IP address in the IP packet header.
The client uses an ephemeral port (a high, randomly chosen port number) for the return traffic.

Port Number Ranges

Ports can be broadly categorized into three types: well-known, registered, and critical.

Well-known ports: This range of ports, from 0 to 1023, is reserved for specific protocols and services. Examples of well-known ports include:
- HTTP (port 80)
- FTP (port 21)
- SSH (port 22)
Registered ports: This range of ports, from 1024 to 49151, is also reserved for specific protocols and services. An example of a registered port is:
- Microsoft SQL Server (port 1433)
Ephemeral ports: 49152-65535 (used for return traffic)

Common Protocols

FTP (File Transfer Protocol) is a widely used protocol for transferring files over the internet. It operates over TCP (Transmission Control Protocol) and typically uses ports 20 and 21. However, it is not a secure protocol as it transmits data in plaintext, making it vulnerable to unauthorized access and eavesdropping.
SFTP is a secure protocol that uses SSH for file transfer, which is advantageous in securing data during transmission by ensuring its confidentiality and integrity. This added layer of security is achieved through public-key cryptography and password authentication, thereby providing an additional safeguard against unauthorized access and tampering. The use of SSH as a secure shell protocol further enhances SFTP's security features.
SSH (Secure Shell): secure protocol for remote access, TCP port 22
FTPS (FTP over SSL/TLS) leverages the Transport Layer Security (TLS) protocol to provide a secure connection for file transfer, utilizing TCP ports 989 and 990. This encrypted tunnel ensures the confidentiality and integrity of transmitted data, safeguarding against eavesdropping and tampering.
Telnet: unsecured protocol for remote access, TCP port 23
SMTP (Simple Mail Transfer Protocol): used for sending mail, TCP port 25
DNS (Domain Name System): used for domain name resolution, TCP or UDP port 53
<tftp> is a streamlined version of <ftp> that utilizes UDP port 69 for transferring files. Despite its name, <tftp> is not truly trivial and is often used for booting devices, retrieving configuration files, and maintaining firmware integrity in network-enabled devices. Its simplicity and efficiency make it a reliable choice for small file transfers over a network.</tftp></ftp></tftp>
DHCP (Dynamic Host Configuration Protocol): used for dynamic IP address assignment, UDP port 67
HTTP (Hypertext Transfer Protocol): used for unsecured web communication, TCP port 80
HTTPS (Hypertext Transfer Protocol Secure): used for secured web communication, TCP port 443
POP3 (Post Office Protocol version 3): used for email retrieval, TCP port 110
IMAP (Internet Message Access Protocol) is a popular protocol used for retrieving email messages from a remote email server. It allows users to access their email accounts from anywhere, reading and managing their messages without having to download the entire email inbox. IMAP uses TCP port 143 and is widely supported by most email clients and servers.
LDAP (Lightweight Directory Access Protocol): used for directory services, TCP port 389
SNMP (Simple Network Management Protocol): used for network device management, UDP port 161
RDP (Remote Desktop Protocol): used for remote desktop access, TCP port 3389
SIP (Session Initiation Protocol): used for voice and video calls, TCP or UDP port 5060
H.323: used for voice and video calls, TCP port 1720
SMB (Server Message Block): used for file sharing, UDP port 445

Database Servers

SQL Server (Microsoft): uses TCP port 1433
Oracle SQL Net: uses TCP port 1521
MySQL: uses TCP port 3306

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