147. Ports and Protocols

Port

Logical communication endpoint that exists on a computer or server

Inbound Port

Logical communication opening on a server that is listening for a connection from a client

Outbound Port

Logical communication opening created on a client in order to call out to a server that is listening for a connection

Port range

0 to 65,535

Well-Known Ports range

o to 1023

Well-Known Ports

Assigned by the IANA

IANA

Internet Assigned Numbers Authority

HTTPS port

443

Telnet port

23

Registered Ports range

1024 to 49,151

Registered Ports

Usually assigned to proprietary protocols

SQL port

1433

RDP port

3389

Dynamic and Private Ports range

49,152 to 65,535

Dynamic and Private Ports

Used by any application without being registered with IANA

Protocol

Rules governing device communication and data exchange

Port 21

TCP

File Transfer Protocol

File Transfer Protocol (FTP)

Used to transfer files from host to host

Port 22

TCP

SSH, SCP. SFTP

SSH

Provides secure remote terminal access and file transfer capabilities

SCP

Provides secure copy functions

SFTP

Provides secure file transfers

Port 23

TCP

Telnet

Telnet

Provides insecure remote control of another machine using a text-based environment

Port 25

TCP

Simple Mail Transfer Protocol

Simple Mail Transfer Protocol (SMTP)

Provides the ability to send emails over the network

Port 53

TCP and UDP

Domain Name System

Domain Name System (DNS)

Translates domain names into IP addresses

Port 69

UDP

Trivial File Transfer Protocol

Trivial File Transfer Protocol

Used as a lightweight file transfer method for sending configuration files or network booting of an operating system

Port 80

TCP

Hypertext Transfer Protocol

Hypertext Transfer Protocol (HTTP)

Used for insecure web browsing

Port 88

UDP

Kerberos

Kerberos

Network authentication protocl

Port 110

TCP

Post Office Protocol Version Three

Post Office Protocol Version Three (POP3)

Responsible for retrieving email from a server

Port 119

TCP

Network News Transfer Protocol

Network News Transfer Protocol (NNTP)

Used for accessing newsgroups

Port 135

TCP and UDP

Remote Procedure Call

Remote Procedure Call (RPC)

Facilitates communication between different system processes

Port 137

TCP and UDP

NetBIOS

Port 138

TCP and UDP

NetBIOS

Port 139

TCP and UDP

NetBIOS

NetBIOS

Networking protocol suite

Port 143

TCP

Internet Message Access Protocol

Internet Message Access Protocol

Allows access to email messages on a server

Port 161

UDP

Simple Network Management Protocol

Simple Network Management Protocol

Manages network devices

Port 162

UDP

SNMP Trap

SNMP Trap

Responsible for sending SNMP trap messages

Port 389

TCP

Lightweight Directory Access Protocol

Lightweight Directory Access Protocol

Facilitates directory services

Port 443

TCP

HTTP Secure

HTTP Secure (HTTPS)

Provides secure web communication

Port 445

TCP

Server Message Block

Server Message Block (SMB)

Used for file and printer sharing over a network

Port 465

TCP

SMTP Secure

Port 587

TCP

SMTP Secure

SMTP Secure (SMTPS)

Provides secure SMTP communication

Port 514

UDP

Syslog

Syslog

Used for sending log messages

Port 636

TCP

LDAP Secure

LDAP Secure (LDAPS)

LDAP communication over SSL\TLS

Port 993

TCP

Internet Message Access Protocol over SSL\TLS

Internet Message Access Protocol over SSL\TLS (IMAPS)

Used for secure email retrieval

Port 995

TCP

Post Office Protocol version 3 over SSL\TLS

Post Office Protocol version 3 over SSL\TLS (POP3S)

Used for secure email retrieval

Port 1433

TCP

Microsoft SQL

Microsoft SQL

Used to facilitate communication with Microsoft SQL Server

Port 1645

TCP

RADIUS TCP

Port 1646

TCP

RADIUS TCP

RADIUS TCP

Used for remote authentication, authorization, and accounting

Port 1812

UDP

RADIUS UDP

Port 181

UDP

RADIUS UDP

RADIUS UDP

Used for authentication and accounting as defined by the Internet Engineering Task Force (IETF)

Port 3389

TCP

Remote Desktop Protocol

Remote Desktop Protocol (RDP)

Enables remote desktop access

Port 6514

TCP

Syslog TLS

Syslog TLS

Used in a secure syslog that uses SSL\TLS to encrypt the IP packets using a certificate before sending them across the IP network to the syslog collector