Access to Jabber.ru (and not only) on non-standard ports

Pro ports Jabber / XMPP and proxy servers

"It is well known" that the main ports of the Jabber protocol are 5222 and 5223, which are very rarely found in the list of ports that are open to the outside on corporate proxy servers.
Probably there are quite a lot of people who tried to go to Jabber, but could not connect to the server, precisely because the proxy server could not / did not want to connect to one of these ports, while “ICQ worked like a clock ! ”(Transparent proxying made itself felt).
I was among these people (with the only difference that I had been able to register a route for myself and set up a proxy). But this opportunity did not appear immediately, but I wanted to use such a wonderful protocol as XMPP.
However, the solution, as expected, was found.

Decision

We are looking for a parameter in our client like “Specify a host for the connection” and indicate the following settings (optional):

ssl.jabber.ru, port 443 (SSL must be enabled)
allports.jabber.ru, any port, but 443 or 80 is recommended (SSL should be disabled)

Important note

Despite the apparent obviousness of the settings, I regularly encounter the fact that people confuse the server and the address to connect to it.

Analogy

We have a mailing address foo@bar.org. Here: foo is the username, bar.org is the mail domain, and smtp.foo.org:25 and pop.foo.org:110 are the addresses and ports of the servers with which the mail client will work. In XMPP, everything is the same, only the server address is one. Therefore, I repeat once again:
')

Important

Addresses and passwords are not entered in the server field (it still remains jabber.ru), but in the Host / Server IP field / Manually specify connection host / Manually specify the host for the connection (depends on the client).

Briefly about ports and encryption

SSL is a traditional encryption method. When SSL is enabled, encryption starts from the very beginning of the data transfer. SSL usually uses a dedicated port 5223
TLS is a newer encryption method based on SSL. A session begins without encryption and is enabled only if it is possible. Works on the same port as Jabber without encryption, usually 5222.