Resolved HTTP2 active... but not use by website

[Erwan]

Server operating system version

AlmaLinux 9.3

Plesk version and microupdate number

18.0.60

Hi all,

HTTP2 is active on the server:

# plesk bin http2_pref --status
Enabled

Website has a certificate (server wildcard certificate), selected in the hosting parameters.
The website works fine with "https".

But when i control the website with https://tools.keycdn.com/http2-test:
HTTP/2 protocol is not supported.

What is the problem ? How can we force the use of http2?

 

[AYamshanov]

Have you tried steps from the Troubleshooting section, HTTP/2 Support in Plesk

 

[Erwan]

Thank you AYamshanov.

It seems that the problem is with ALPN (module Apache negociation ?).
When i check with https://tools.keycdn.com/http2-test, result is: ALPN extension is not supported.

ALPN support for nginx web server is available in Plesk for the following operating systems: CentOS 7, RedHat Enterprise Linux 7, and Debian 8.

And AlamLinux 9? I don't found information.

The rest is ok except n°5 but is "TLSv1 TLSv1.1 TLSv1.2"" and for me "TLSv1 TLSv1.1 TLSv1.2 TLSv1.3"...

 

[Erwan]

I think the problem is because we use server wildcard certificate. I've no problem with others servers and Almalinux 9.

So, i've choose this certificate, and https works fine but in Plesk says: Problems with certificate.

My wilcard certificate is for: "mydomain.com". So, it can be used for "*.mydomain.com".
I install it on the server. And i use it for:
- website 1: "w1.mydomain.com". No problem all is ok. But Plesk message: problems with certificate.
"w1.mydomain.com" => ok
"www.w1.mydomain.com" => not ok. But i've selected i want only "w1.mydomain.com" in website parameters (prefer).

If i create another website "mydomain2.com" and activate a let'sencrypt certificate, http2 is ok with the website.

I need to use this wildcard certificate.
How do I get Plesk to understand that everything is working and that it can allow http2?

 

[AYamshanov]

ALPN support for nginx web server is available in Plesk for the following operating systems: CentOS 7, RedHat Enterprise Linux 7, and Debian 8.

And AlamLinux 9? I don't found information.

The rest is ok except n°5 but is "TLSv1 TLSv1.1 TLSv1.2"" and for me "TLSv1 TLSv1.1 TLSv1.2 TLSv1.3"...

Thank you for the feedback, I will ask the documentation team to review the text because this part looks outdated. Of course, Plesk supports HTTP/2 on modern OSes as well as on RHEL7-based and Debian 8.

"w1.mydomain.com" => ok
"www.w1.mydomain.com" => not ok.

I think this is because wildcard covers only one level of subdomains (*.mydomain.com and not *.*.mydomain.com).
> "RFC 2818 - HTTP Over TLS". Internet Engineering Task Force. May 2000. p. 5. Retrieved 2014-12-15. [...] *.a.com matches foo.a.com but not bar.foo.a.com. (c) Wildcard certificate - Wikipedia

 

[Erwan]

Ok i found the problem.
Calls go through a loadbalancer which does not support HTTP2.
Live tests indicate that HTTP2 is handled correctly.

Thanks for the help.