# The lingering legacy of 'reserved' ports

DevFeed: [The lingering legacy of 'reserved' ports](<https://devfeed.tech/articles/the-lingering-legacy-of-reserved-ports-10853.md>)

Original publisher: [Read original article](<https://blog.apnic.net/2026/08/28/the-lingering-legacy-of-reserved-ports/>)

Author: George Michaelson

Published: 2026-08-27T23:29:48Z

Content type: article

Language: en

Sources: [APNIC Blog](<https://devfeed.tech/sources/apnic-blog.md>)

Topics: [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>), [Network](<https://devfeed.tech/topics/network.md>), [Process](<https://devfeed.tech/topics/process.md>), [Operating system](<https://devfeed.tech/topics/operating-system.md>), [Unix](<https://devfeed.tech/topics/unix.md>), [ssh](<https://devfeed.tech/topics/ssh.md>), [Firewall](<https://devfeed.tech/topics/firewall.md>), [Internet](<https://devfeed.tech/topics/internet.md>)

Tags: [dns](<https://devfeed.tech/tags/dns.md>), [firewall](<https://devfeed.tech/tags/firewall.md>), [history](<https://devfeed.tech/tags/history.md>), [internet](<https://devfeed.tech/tags/internet.md>), [network](<https://devfeed.tech/tags/network.md>), [ntp](<https://devfeed.tech/tags/ntp.md>), [opinion](<https://devfeed.tech/tags/opinion.md>), [process](<https://devfeed.tech/tags/process.md>), [processes](<https://devfeed.tech/tags/processes.md>), [ssh](<https://devfeed.tech/tags/ssh.md>), [systems](<https://devfeed.tech/tags/systems.md>), [tech-matters](<https://devfeed.tech/tags/tech-matters.md>)

## AI overview

An exploration of why reserved TCP and UDP ports persist, tracing conventions such as ports 22, 53, 80, and 443 to early Internet services on multi-user systems. It explains the relationship between ports, protocol-specific daemons, operating-system administration, and modern firewall and service-discovery practices.

## Source excerpt

Modern service discovery mechanisms increasingly allow services to run on arbitrary ports, yet DNS may remain the one protocol that cannot fully escape its dependency on the long-established convention of port 53.