Client connections through HTTPS port

It’s possible to enable the client to connect through port 443 (the HTTPS port), which can allow bypassing some very restrictive firewalls.

Firstly, you need to set up sslh, as described in the reverse proxy documentation. Then you need to add the following SRV record: 86400 IN SRV 0 0 443

Unfortunately SRV records setup varies widely between different DNS providers, so you’ll need to figure out which info to put where yourself, based on the example records shown here.