Mike Schwab wrote: >Port 23 is standard telnet. Port 3270 is non-standard TN3270E.
IANA has actually reserved port 3270 for "Verismart": https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt I have no idea what Verismart is, or was. It's probably moribund, like many port reservations. You're not obliged to honor IANA's reservations and recommendations, although it's the "polite thing to do." If nothing else it makes the job of somebody monitoring, managing, and troubleshooting network traffic a little easier, because at least you give that person a clue what the traffic is about. IANA has reserved port 992 for Telnet, including TN3270/TN3270E, over TLS. So one common, IANA-polite approach is to enable port 992 first then, if needed, port 23 second, *both* with TN3270E over TLS. (Yes, OSA-ICC supports TN3270E over TLS. Use it, please.) IANA also leaves ports 49152 and above as "private use" ports, so you can use ports 50001, 50002, 50023, etc. -- a 5 followed by any 4 digits works well -- as recklessly as you want. Ports 50992 and 50023 should give above average network troubleshooters some clue that the traffic is telnet-oriented. As far as non-standard ports, the following are at least IANA reserved for some sort of "telnet": 89, 107, 902, 903, 1618, 2564, 3083, 3696, 5024, and 6623. Some of them are moribund. So if you'd like to use one or more of these ports "in the spirit of IANA," that's up to you. :-) Port 22 is assigned to SSH, and again "in the spirit of IANA" perhaps you could use that one for TN3270E over TLS if you need it. - - - - - - - - - - Timothy Sipples I.T. Architect Executive Digital Asset & Other Industry Solutions IBM Z & LinuxONE - - - - - - - - - - E-Mail: sipp...@sg.ibm.com ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
