Connexion to backend proxied server serving HTTPS over TLSv1.3 only will fail

[bynicolas]

If we reverse proxy to an internal server that is serving content explicitly and only over TLSv1.3, then you will get a 502 Bad Gateway error.

I did some digging and the issue is clearly happening in the server block of the proxy. You can find the discussions here https://forum.nginx.org/read.php?11,294147 and here https://unix.stackexchange.com/questions/706074/nginx-reverse-proxy-fails-with-tlsv1-3-on-backend-servers

So this is easily fixable by adding proxy_ssl_protocols TLSv1.3; to the Custom Nginx Configuration block in the Advanced tab of the proxy host in question.

Having to manually edit each host is not ideal though; this should maybe be improved in a future release as TLSv1.3 is more widely used.

Maybe adding a toggle switch saying something like TLSv1.3 only destination on the details or SSL tabs to enable this setting?

Nginx Proxy Manager Version
v2.9.18

[the1ts]

@bynicolas its already waiting for merging (#2045).

[bynicolas]

Cool, that's great. Sorry about the bug report then, I guess my search terms weren't wide enough!