Discover how IANA plays a vital role in managing global internet protocols and port numbers. This guide covers 50 essential networking protocols you must know for your IT and cybersecurity career in 2025!
Discover how IANA plays a vital role in managing global internet protocols and port numbers. This guide covers 50 essential networking protocols you must know for your IT and cybersecurity career in 2025!
IANA (Internet Assigned Numbers Authority) is a critical organization in the infrastructure of the internet. It is responsible for the global coordination of IP addressing, Domain Name System (DNS) root zones, protocol assignments, and port number management. Operating under ICANN (Internet Corporation for Assigned Names and Numbers), IANA ensures that the internet functions seamlessly by avoiding conflicts in global network communications.
Why IANA Matters:
- IP Address Allocation: IANA distributes IP address blocks to Regional Internet Registries (RIRs) like APNIC, ARIN, RIPE, etc.
- Domain Name Management: Manages DNS root zones including Top-Level Domains (TLDs) such as .com, .org, .net, and country codes like .in, .uk.
- Protocol Number Assignment: Assigns protocol numbers used in the IP header for protocols like TCP, UDP, and ICMP.
- Port Number Registration: Maintains a global registry of TCP and UDP ports to ensure proper application mapping.
What Are Networking Protocols?
Networking protocols are a set of rules that define how data is formatted, transmitted, and processed across network devices. These protocols enable computers and devices to communicate over local and wide area networks, including the internet.
The OSI (Open Systems Interconnection) and TCP/IP models classify these protocols into multiple layers, from physical to application.
Top 50 Common Networking Protocols (2025):
Here is a comprehensive table of the 50 most common networking protocols categorized by their OSI or TCP/IP layer, function, and usage port if applicable:
| # | Protocol | Layer / Port | Purpose |
|---|---|---|---|
| 1 | TCP | Transport (L4) | Reliable, connection‑oriented transport |
| 2 | UDP | Transport (L4) | Connectionless transport |
| 3 | ICMP | Network (L3) | Ping, error messaging |
| 4 | ARP | Data Link (L2) | MAC ↔ IP mapping |
| 5 | HTTP | Application (TCP 80) | Web traffic |
| 6 | HTTPS | Application (TCP 443) | Secure web traffic |
| 7 | FTP | Application (TCP 20/21) | File transfer |
| 8 | SSH | Application (TCP 22) | Secure shell access |
| 9 | SMTP | Application (TCP 25) | Email sending |
| 10 | DNS | Application (TCP/UDP 53) | Domain name resolution |
| 11 | TFTP | Application (UDP 69) | Simple file transfer |
| 12 | POP3 | Application (TCP 110) | Email retrieval |
| 13 | IMAP | Application (TCP 143) | Email retrieval |
| 14 | NTP | Application (UDP 123) | Time synchronization |
| 15 | SNMP | Application (UDP 161) | Network management |
| 16 | BGP | Network (TCP 179) | Border Gateway Protocol for routing |
| 17 | OSPF | Network (IP Protocol 89) | Link-state routing protocol |
| 18 | RIP | Network (UDP 520) | Distance-vector routing |
| 19 | IGMP | Network (IP Protocol 2) | Multicast group management |
| 20 | IS-IS | Network | Interior gateway routing protocol |
| 21 | Telnet | Application (TCP 23) | Unencrypted remote terminal |
| 22 | LDAP | Application (TCP 389) | Directory access |
| 23 | LDAPS | Application (TCP 636) | Secure directory access |
| 24 | SMB | Application (TCP 445) | File and printer sharing |
| 25 | NetBIOS | Session (UDP 137-139) | Legacy network service |
| 26 | RDP | Application (TCP 3389) | Remote desktop |
| 27 | DHCP | Application (UDP 67/68) | Dynamic IP assignment |
| 28 | MQTT | Application (TCP 1883) | Lightweight IoT messaging |
| 29 | SIP | Application (UDP 5060) | VoIP signaling |
| 30 | SMTPS | Application (TCP 465) | Secure SMTP |
| 31 | IMAPS | Application (TCP 993) | Secure IMAP |
| 32 | POP3S | Application (TCP 995) | Secure POP3 |
| 33 | SFTP | Application (TCP 22) | Secure file transfer |
| 34 | FTPS | Application (TCP 990) | FTP over SSL |
| 35 | GRE | Network | Encapsulation for tunneling |
| 36 | ESP | Network | IPsec encryption protocol |
| 37 | AH | Network | IPsec authentication header |
| 38 | IPSec | Network | Secure IP communication |
| 39 | GTP | Network | Mobile network tunneling |
| 40 | LLDP | Data Link | Link Layer Discovery Protocol |
| 41 | STP | Data Link | Spanning Tree Protocol |
| 42 | CDP | Data Link | Cisco Discovery Protocol |
| 43 | VXLAN | Network | Overlay network virtualization |
| 44 | ICMPv6 | Network | Error messages in IPv6 |
| 45 | ND | Network | Neighbor Discovery (IPv6) |
| 46 | DOT | Application (TCP 853) | DNS over TLS |
| 47 | DOH | Application (TCP 443) | DNS over HTTPS |
| 48 | QUIC | Transport (UDP) | Secure, fast HTTP/3 transport |
| 49 | SRTP | Application | Secure RTP for VoIP |
| 50 | RTP | Application | Real-time Transport Protocol for media |
Real-World Applications:
- Enterprise Networks: Use protocols like BGP, OSPF, SNMP, and RDP for routing, monitoring, and remote access.
- Web Hosting: Relies on HTTP, HTTPS, FTP, DNS, and TLS for secure and efficient service delivery.
- Cloud Infrastructure: Uses REST APIs, HTTPS, SSH, and SFTP for management and data exchange.
Conclusion
Understanding IANA and the top networking protocols is essential for anyone pursuing a career in cybersecurity, system administration, or network engineering. These protocols are the backbone of global communication, and IANA ensures they are standardized and conflict-free. By learning how these protocols work and are categorized, professionals can build more secure and efficient network systems.