Ports Flashcards
Well-Known Ports
Ports 0 to 1023 are considered well-known and are assigned by the Internet Assigned Numbers Authority (IANA)
Registered Ports
Ports 1024 to 49,151 are registered with IANA and are the usually assigned to proprietary protocols.
Dynamic or Private Ports
Ports 49,152 to 65,535 can be used by any application without being registered with IANA. Usually used for temporary outbound connections, gaming and instant message chats.
FTP
File Transfer Protocol; Port 20, 21
Transfers computer files between a client and a server on a computer network; data is in the clear.
SSH
Secure Shell; Port 22
Secure remote control of another machine using a text-based environment.
Cryptographic network protocol for operating network services securely over an unsecured network; best know for remote login to computer systems using a command shell
SFTP
SSH File Transfer Protocol; Port 22
Using FTP for file access, file transfer, and file management through a secure shell tunnel.
Telnet
Telnet; Port 23
Insecure remote access via a command prompt. Very similar to SSH, but it is not secure; everything is sent in the clear (not encrypted). It should never be used on an insecure network (like the internet) because username, password, everything is in the clear.
SMTP
Simple Mail Transfer Protocol; Port 25
Internet standard for sending electronic messages. Think SMTP when sending mail.
DNS
Domain Name Service; Port 53
DNS converts domain names to IP addresses or IP addresses to domain names.
Hierarchical, decentralized naming system for computer, services, or other resources connected to the internet or a private network.
DHCP
Dynamic Host Control Protocol; Port 67, 68
DHCP automatically assigns IP addresses and other network configuration parameters to network clients.
TFTP
Trivial File Transfer Protocol; Port 69
Transmits files in both directions (client to server AND server to client) using an application. Usually used for requesting configuration files from a router or a switch or booting up an operating system from a network drive. It doesn’t provide any authentication.
It’s basically a stripped down version of FTP.
HTTP
Hypertext Transfer Protocol; port 80 - unsecured web-browsing.
POP3
Post Office Protocol v3; Port 110
Used by local email clients to retrieve emails from a remote server over TCP connection.
Think downloading email files to your computer so you can read it offline.
NTP
Network Time Protocol; Port 123
Clock sync between computer systems (additional detail: clock sync over packet-switched, variable-latency data networks).
Remember: Port 123, like keeping time.
NetBIOS
Network Basic Input/Output System; Port 139
NetBIOS provides services allowing applications on separate computers to communicate over a LAN connection for file and printer sharing
IMAP
Internet Mail Application Protocol; Port 143
IMAP allows a client to retrieve email from a mail server over a TCP connection; the users can view and manipulate messages as if they were on the locally while still leaving the messages on the remote system. IMAP keeps all your devices synced RE what emails have been read. IMAP is best for modern email. POP3 isn’t used by most people, but it is still used for server to server email sometimes.
Remember: Port 143, receive emails.
POP3 can also be used to receive emails.
Sending emails is SMTP over port 25.
SNMP
Simple Network Management Protocol; Port 161
SNMP collects and organizes information about managed devices on your IP networks (like routers and switches).
LDAP
Lightweight Directory Access Protocol; Port 389
Open, vendor-neutral, indurstyr standard for accessing and maintaining a distributed directory of inormatino services. LDAP and Active Directory both use port 389.
Remember: it’s a directory, like a phone book
HTTPS
HTTP Secure; port 443 Adds security (TLS or SSL) to the insecure HTTP Protocol
SMB
Server Message Block; Port 445
SMB provides shared access to files, printers, and misc communications between deives on a network.
SMB is used together with NetBIOS.
NetBIOS is more focused on the authentication;
SMB sends the files to you.
LDAPS
LDAP Secure; Port 636
Just like LDAP, but adding encription (TLS/SSL) to make it more secure.
RDP
Remote Desktop Protocol; Port 3389
Proprietary protocol by Microsoft with provides a users with a graphical interface to connect to another computer over a network connection.
SSH or Telnet allows you a command line way to control another computer.
RDP allows you to use a keyboard and mouse to control that other computer.
SIP
Session Initiation Protocol; Port 5060, 5061
Provides signaling and controlling multimedia communication sessions in applications. Used for VOIP, video calls, voice calls, and instant messaging.
VNC
Virtual Network Computing; Port 5900
Designed for things like VDI.
Works like RDP, but it works for all platforms (Windows, Linux, and Mac OS
