Actually, not even Winlink complies anymore, unless you take steps to force the backup path. The default telnet connection uses SSL:
*** Connecting to a CMS...
*** Connected to CMS-SSL at 2019/09/08 23:43:12
[WL2K-5.0-B2FWIHJM$]
;PQ: 13183958
CMS>
;FW: NS7C WA7AUB|93065899
[RMS Express-1.5.23.0-B2FHM$]
;PR: 43469133
; WL2K DE NS7C (CN87WH)
FC EM YL830D4PUQ82 265 225 0
F> BA
FS Y
*** Sending YL830D4PUQ82.
FF
*** Completed send of message YL830D4PUQ82
*** Sent 1 message. Bytes: 259, Time: 00:00, bytes/minute: 30409
FQ
*** --- End of session at 2019/09/08 23:43:18 ---
*** Messages sent: 1. Total bytes sent: 259, Time: 00:05, bytes/minute: 2888
*** Messages Received: 0. Total bytes received: 0, Total session time: 00:05, bytes/minute: 0
*** Disconnecting
*** Disconnected at 2019/09/08 23:43:18
---------
And from the link test:
Test started 2019/09/08 23:46 UTC
Testing CMS telnet connection to
cms.winlink.org through port 8772...
Successfully connected to a CMS through port 8772 in 260 Milliseconds
Testing CMS SSL telnet connection to cms.winlink.org through port 8773...
Successfully connected to a CMS through port 8773 in 328 MillisecondsTesting API service access through port 443 to api.winlink.org...
Successfully performed API service to
api.winlink.org thorugh port 443 in 0 Milliseconds
Testing Autoupdate server access through port 443 to autoupdate2.winlink.org...
Successfully checked autoupdate server thorugh port 443 in 334 Milliseconds
Testing connection to web site -
www.winlink.org:80 Successfully connected to
www.winlink.org thorugh port 80 in 37 Milliseconds
Testing FTP connection to SFI site -
ftp://ftp.swpc.noaa.gov/pub/latest/SGAS.txt Successfully connected to
ftp://ftp.swpc.noaa.gov/pub/latest/SGAS.txt thorugh port 20/21 in 2004 Milliseconds
Test completed successfully.
--------
It will fall back to a non-SSL connection if the SSL connection fails, so if you block port 8773 on the local firewall, it will go non-SSL:
Test started 2019/09/09 00:08 UTC
Testing CMS telnet connection to
cms.winlink.org through port 8772...
Successfully connected to a CMS through port 8772 in 147 Milliseconds
Testing CMS SSL telnet connection to
cms.winlink.org through port 8773...
Error: --> Unable to connect to a CMS through port 8773Testing API service access through port 443 to api.winlink.org...
Successfully performed API service to
api.winlink.org thorugh port 443 in 527 Milliseconds
Testing Autoupdate server access through port 443 to autoupdate2.winlink.org...
Successfully checked autoupdate server thorugh port 443 in 206 Milliseconds
Testing connection to web site -
www.winlink.org:80 Successfully connected to
www.winlink.org thorugh port 80 in 31 Milliseconds
Testing FTP connection to SFI site -
ftp://ftp.swpc.noaa.gov/pub/latest/SGAS.txt Successfully connected to
ftp://ftp.swpc.noaa.gov/pub/latest/SGAS.txt thorugh port 20/21 in 1528 Milliseconds
Test completed. Errors were detected.
--------
And Telnet connection:
*** Connecting to a CMS...
*** Connected to CMS at 2019/09/09 00:08:28
[WL2K-5.0-B2FWIHJM$]
;PQ: 77080554
CMS>
;FW: NS7C WA7AUB|57184971
[RMS Express-1.5.23.0-B2FHM$]
;PR: 55962530
; WL2K DE NS7C (CN87WH)
FF
FQ
*** --- End of session at 2019/09/09 00:08:29 ---
*** Messages sent: 0. Total bytes sent: 0, Time: 00:00, bytes/minute: 0
*** Messages Received: 0. Total bytes received: 0, Total session time: 00:00, bytes/minute: 0
*** Disconnected at 2019/09/09 00:08:34
----------
You probably have to block autoupdate as well.....
-Scott, NS7C