Question 1

What port is 8080 and why is it used as an alternative to 80?

Accepted Answer

Port 8080 is the standard HTTP Alternate port. On Unix and Linux systems, ports below 1024 are privileged and require root or administrator access to bind to. Port 8080 allows developers and application servers (such as Apache Tomcat, Jenkins, Spring Boot, or local proxies) to host HTTP web applications without requiring root execution privileges.

Question 2

What is the difference between Well-Known, Registered, and Dynamic Ports?

Accepted Answer

RFC 6335 establishes three standardized port ranges: • Well-Known Ports (0–1023): Assigned to foundational network protocols (HTTP 80, SSH 22, DNS 53); requires system privileges. • Registered Ports (1024–49151): Listed by IANA for specific vendor software and database daemons (MySQL 3306, Redis 6379, RDP 3389). • Dynamic / Ephemeral Ports (49152–65535): Used temporarily by client operating systems for outbound sessions.

Question 3

Which ports are most commonly targeted by automated ransomware and botnets?

Accepted Answer

The most actively probed attack surfaces on the public Internet include Port 445 (SMB, exploited by EternalBlue MS17-010), Port 3389 (RDP, targeted by credential brute-forcers), Port 23 (Telnet, hijacked by Mirai IoT botnets), and unauthenticated data stores like Port 6379 (Redis) and Port 27017 (MongoDB). These services should always be sequestered behind private VPC subnets or VPNs.

Question 4

How does No matching ports found work in TCP / UDP Common Port Directory & Security Reference?

Accepted Answer

Try adjusting your search query, choosing "All Categories", or testing the port in the "Quick Lookup" tab.

TCP / UDP Common Port Directory & Security Reference — Guide de référence

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Tune Sort Field & Sort Asc Together

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Unexpected output or validation warning in TCP / UDP Common Port Directory & Security Reference

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