Port: 21
FTP is the protocol that handles transfering files from one device to another. It operates by considering one device as a server and the other as a client, thereby allowing the client to send and request files from the server
FTP/S
Port: 900
This protocol allows FTP over a secure encryption using SSL.
SFTP
This protocol allows FTP over a secure encryption using SSH.
Port: 80
HTTP is the protocol that handles the transfer of hypertext between one or multiple systems. It is designed using the client-server principles; allowing a client to make a request after forming a connection with the server, at which point the server responds however it is programmed.
HTTPS
Port: 443
This protocol allows HTTPs over a secure encryption using SSL.
Ports: 25,465,587
SMTP is the protocol that handles the task of sending and then distributing E-Mail. It operates by seperating strings of text from the users message with code words that identify the purpose of each string and that the server can interpret. The messages can sometime pass through other devices other than it's destination.
Port: 110
POP3 is the protocol that handles receiving e-mails that are unsecure. It operates by downloading messages to a local device and then removing it from the e-mail server.
Ports: 143, 993
IMAP4 is the protocol that handles secure e-mail aquisition by accessing a remote server with a local client.
Port: 22
SSH is the protocol that secures a connection between a client and a server. This operates by creating a tunnel using cryptographic keys between the client and the server. This allows secure communication between the 2 devices.
Port: 23
Telnet is a group of rules that systems follow when trying to establish a remote connection. It operates by allowing a two-way CLI connection to the remote device.
Port: 161
SNMP is the protocol that handles network monitoring. It operates by communicating with devices that "speak" SNMP using Get-Requests, allowing the user to be able to track any data values specified.
Port: 219
ARP is the protocol that handles mapping dynamic IP addresses to a physical MAC address. It operates on Layer 2 and Layer 3 by keeping a cache of unique IP address and their equivalent MAC address. If, when a request is made, the requested address is already in the cahce, it is just returned. Otherwise, it translates and finds the equivalent address.