Developer Tatu Ylonen disclosed by Mr. Tatu Ylonen how the port number of SSH was set to "22"

Secure Shell (SSH)Was a protocol for securely communicating with a remote computer, was a student at the timeTatu YlonenIt is a technology that Mr. developed. "22" is specified as the default port of SSH, but Mr. Ylonen reveals the circumstances determined to No. 22 by using the mail at the time.

SSH Port
https://www.ssh.com/ssh/port

Mr. Ylonen, a student at the Helsinki University of Technology in Finland in 1995, wrote a program to securely connect to another machine. At that time, there were Telnet and FTP as existing protocols that use the shell of the remote host, but since both passwords are transmitted on the network in clear text, there was a problem in terms of security. Therefore, Mr. Ylonen thought about designing an alternative program to Telnet and FTP, and developed "Secure Shell (SSH)".

Since port number used by FTP is "21", port number used by Telnet is "23" and "22" therebetween was not used, Ylonen uses port 22 in its own test environment and SSH It is said that he did development of.

At that time it was the early Internet era when the Internet bubble (dot com bubble) had not arrived yet, the Internet Assigned Numbers Authority (IANA) was doing the assignment of the port number. That is,Jon PostelMr. orJoyce K. ReynoldsThe heavyweights of Mr. and others' pioneering existence of Internet technology had the decision power. Mr. Ylonen said that these heavyweights were terrible beings.

Mr. Ylonen sent a mail to IANA on July 10, 1995, just prior to the release of SSH - 1.0. It is written in the following sentence: "Writing a program to conduct secure communication" "Software is planned to be distributed free for many people to use" "1 to 255 range I want to acquire the privileged port in "" I am trying to obtain the service name of software "SSH" "and I am currently using the port number" 22 "in the beta test, it is still assigned to the list It would be wonderful if you could use a number that was not available ".


The next day, Mr. Ylonen received a mail from Mr. Reynolds that "I assigned port number 22 to SSH".


Mr. Ylonen who received the mail announced the final beta version at Helsinki Institute of Technology at 2:32 am on July 12, 1995, released the ssh - 1.0.0 package at 5:23 pm, and the newsgroup and mailing list , It seems to have announced the release of SSH mail to the celebrity who is discussing on the Internet.

After that, Mr. Ylonen received the inquiry as to whether SSH can be sold as a product, and established SSH Communication Security, and in just five years it made an organization with sales of 20 million dollars, employment number 190 people, SSH is still in communication It has been developed as a protocol used in.


The background that 22 is used as the default port number of SSH seems to have been decided by IANA that received a mail from a Finnish student and assigned port number 22.