How SSH got port number 22
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Submission timeline
2007–2026One slot for every year since HN launched. Height is that year's peak points; orange marks a 100+ point or 50+ comment breakout. Select a bar to open its strongest thread.
First comments on top threads
HN comment orderA more interesting story is why are the older services using mainly odd port numbers (ie. 21 = FTP, 23 = telnet, why was port 22 free at that time?). It turns out because the protocol which preceded the invention of TCP, called NCP, used even-odd pairs of port numbers, with even for "outgoing" data and odd for "incoming". So the well-known port numbers for incoming services were all odd. Sources: https://en.wikipedia.org/wiki/Network_Control_Program http://www.pcvr.nl/tcpip/introduc.htm
So the crux of the story is “I had to email an internet icon and she mailed me back right away having done what I asked”. I can sympathize. When I worked at Sendmail I was tasked with running DNS for the company, which included Sendmail.org. The first thing I had to do was find a secondary DNS. Our founder said to “email his friend Paul”. It turned out his friend was Paul Vixie, the inventor of BIND, who responded…
While the copies of the original emails are mildly interesting, it looks like the answer is just "Because I asked for port 22 and got it".
The first top-level comment from each of the four biggest threads, in HN’s own order. Excerpts are shortened; open a comment for full context.
- Breakout years
- 3
- Total points
- 1614
- Total comments
- 383
100+ points or 50+ comments
reference only — not used in Hall rules or ranking
reference only — not used in Hall rules or ranking
Every submission
| Date | Title as submitted | By | Points | Comments |
|---|---|---|---|---|
| 2017-04-20 | The Story of Getting SSH Port 22 | pekko | 1 | 0 |
| 2017-04-23 | How SSH got port number 22First breakout · Best thread | kissgyorgy | 1034 | 207 |
| 2018-07-17 | How SSH port became 22 | ronsor | 197 | 95 |
| 2019-10-24 | How SSH Port Became 22Latest 20+ point return | kawera | 382 | 81 |