HOW MANY NETWORK PROTOCOLS EXIST?

Let me tell you 18 Important protocols that a network engineer must know.
Before we jump in let us divide these 18 Important protocols into :-

TCP (Transmission control protocol)
aka connection oriented protocol — Port No : 06
It works on transport layer of OSI (Open System Interaction) Model.
It is three way handshake.

List of TCP Protocols:-

• FTP (File Transfer Protocol) : It transfers file/folders/document/data between two devices. It does not matter that file transfer is happening in same network or completely different network.
• Port No : 20
• Port No : 21 (for establishing and maintaining connection)
• TFTP (Trivial File Transfer Protocol) : FTP asks for username and password. whereas TFTP doesn’t.
• Port No : 69
• SFTP (Secure File Transfer Protocol) : It encrypts the data. It is more secure than FTP & TFTP.
• Port No : 22 (Secure shell)
• TELNET : It is used for accessing the device/ system remotely & not secure at all. No GUI, configured using CMD.
• Port No : 23
• e-Mailing services also use TCP:-
• SMTP(Simple Mail Transfer Protocol) : It is used by mail server to communicate with another mail server.
• Port No : 25
• Port No : 465 ( Port is secured using TLS & SSL)
• IMAP4 (Internet Mail Access Protocol) : It downloads a copy of mail from the mail server whereas original mail is still on the server.
• Port No : 143
• Port No : 993 ( Port is secured using TLS & SSL)
• POP3 (Post Office Protocol 3) : It downloads the original mail from the mail server, Saves it physically in your computer and if you delete that mail it will be completely vanished from server too. you can’t get it back.
• Port No : 110
• Port No : 995 (Port is secured using TLS & SSL)
• HTTP (Hyper Text Transfer Protocol): It is makes you to see a web page.
• Port No : 80
• HTTPS (Hyper Text Transfer Protocol Secure): Http turns into https for making itself more secure.
• Port No : 443 (Port is secured using TLS & SSL)

UDP (User Datagram Protocol)
aka connection less protocol — Port No : 17

List of UDP Protocols:-

• SNMP (Simple Network Management Protocol) : It gathers information of the network infrastructure like active routers, switches, firewalls, servers, etc and sends this information to admin.
• Port No : 161
• Port No : 162 (secure Port using Transport layer security)
• NTP (Network Time Protocol) : It synchronizes servers on time for providing applications and other services to clients.
• Port No : 123
• SIP ( Session Initiation Protocol) : It works with Video and voice.
• Port No : 5060
• Port No : 5061 (secure Port using Transport layer security)
• RTSP ( Real Time Streaming Protocol) : it is used by servers for streaming media like youtube.
• Port No : 554
• DHCP ( Dynamic Host Configuration Protocol) : It dynamically provides ip address, subnet mask, default gateway, dns a complete tcp/ip setting to a device actively connected to network. Small companies uses DHCP in router while big companies uses it in servers.
• Port No : 67
• Port No : 68

TCP & UDP Both

• LDAP (Lightweight Directory Access Protocol) : It has a directory(active directory) of all the data related to Network System like username of person using device (first name, last name etc), password & other details of user, name of devices( printers/switches/routers/servers etc).
• Port No : 389
• RDP (Remote Desktop Protocol): It uses windows. it connects & manages the computer remotely(probably miles away.
• Port No : 3389
• DNS (Domain Name System) : Huge Protocol. It is used for remembering domain names like facebook.com, youtube.com. As we know that system works in binary but we humans are more comfortable with names and decimal numbers. Humans write names of websites and DNS converts that name into numbers (IP address) so that system can understand the request and user can get the desired result.
• Port No : 53

TCP & UDP are the huge protocols out there and all others protocols basically rely on either TCP or UDP or Both, which works on the transport layer of OSI (Open System Interaction) Model.