Networking
has evolved beyond cables and routers; it's now the backbone of cloud
computing, remote work, IoT, 5G, and zero-trust architectures.
According
to a 2025 report by Cisco, network traffic is expected to surpass 600 exabytes
per month, driven by AI workloads, hybrid infrastructures, and edge
computing.
Amidst
this growth, TCP/IP protocols remain the
foundation, powering everything from entry-level support to advanced network
engineering.
Top TCP/IP Protocols You Must Know
1. TCP (Transmission Control Protocol):
Ports vary (HTTP [80], HTTPS [443], FTP [21])
Reliable, connection-oriented protocol for accurate, ordered delivery.
2. IP (Internet Protocol):
N/A (IP is a Layer 3 protocol)
Handles addressing and routing across networks. IPv4 and IPv6 both matter.
3. UDP (User Datagram Protocol):
Ports vary (DNS [53], SNMP [161], etc.)
A faster, connectionless protocol used for real-time services.
4. HTTP (Hypertext Transfer Protocol):
Port 80
Enables web browsers to request and load pages from servers.
5. HTTPS (Hypertext Transfer Protocol Secure):
Port 443
The secure version uses SSL/TLS to encrypt data in transit.
6. FTP (File Transfer Protocol):
Ports 20 (data), 21 (control)
Facilitates file exchange between client and server; less secure than modern alternatives.
7. SFTP (SSH File Transfer Protocol):
Port 22
A secure alternative to FTP that runs over SSH for encrypted file transfers.
8. SMTP (Simple Mail Transfer Protocol):
Ports 25, 465 (SSL), 587 (TLS)
Handles sending emails; critical in mail server configurations.
9. IMAP (Internet Message Access Protocol):
Ports 143 (default), 993 (SSL)
Syncs email across multiple devices and stores mail on the server.
10. POP3 (Post Office Protocol v3):
Port 110, 995 (SSL)
Downloads mail to local devices; largely outdated but still used in some systems.
DNS (Domain Name System):
11. Port 53 (UDP/TCP)
Resolves domain names to IP addresses; essential for internet functioning.
12. DHCP (Dynamic Host Configuration Protocol):
Ports 67 (server), 68 (client)
Dynamically assigns IP addresses and configures network devices.
13. SNMP (Simple Network Management Protocol):
Ports 161 (UDP), 162 (for traps)
Monitor, manage, and configure network devices, such as routers and switches.
14. ICMP (Internet Control Message Protocol):
No port (used at IP level)
Used for diagnostics and network health (e.g., ping, traceroute).
15. NTP (Network Time Protocol):
Port 123 (UDP)
Keeps system clocks in sync. Inaccurate time can break logs, authentication, and certificates; NTP ensures everything lines up.
16. TELNET:
Port 23
Legacy protocol for remote terminal access; insecure, rarely used today.
17. SSH (Secure Shell):
Port 22
Secure remote access to devices; widely used for admin tasks.
18. RDP (Remote Desktop Protocol):
Port 3389
Allows graphical remote access to Windows machines.
19. TFTP (Trivial File Transfer Protocol):
Port 69 (UDP)
Lightweight version of FTP used for booting devices (PXE) and pushing configs to routers/switches.
LDAP (Lightweight Directory Access Protocol):
Port 389 (unencrypted), 636 (SSL)
Used to access and manage directory services like Active Directory.
20. BGP (Border Gateway Protocol):
Port 179 (TCP)
Manages routing between large networks and ISPs.
In
today’s world of AI, automation, and cloud computing, foundational knowledge
might seem outdated, but it is more relevant than ever. Every cloud transaction
still runs over TCP/IP. Most security breaches stem from misconfigured ports
and overlooked protocols. Network failures? Often caused by someone who didn’t
fully grasp the underlying infrastructure.
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