Apache reverse proxy HTTPS to HTTPS

Can Apache reverse proxy with HTTPS pages?

                       client
                          |
                  Apache reverse proxy
                  https://example.com
                  https://example.net 
                  https://example.org
                      192.0.2.1
                          |
         -----------------------------------------
         |                |                      |
https://example.com   https://example.net   https://example.org
192.0.2.2:1234        198.51.100.3:5678     203.0.113.4:9012

Yes, but if you wish to validate the certificates on your back-ends it is better to have separate hostnames for them. Also, example.com cannot resolve both to the reverse proxy and the back-end server at the same time. You would need to do some unnecessary – even hacky – configuration for the certificate renewals & local DNS.

You need to have both mod_ssl & mod_proxy enabled.

Example with client --> https://example.com/ --> https://backend.example.com:1234/:

<VirtualHost *:443>
    ServerName example.com

    SSLEngine on
    SSLCertificateFile /etc/letsencrypt/live/example.com/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/example.com/privkey.pem

    SSLProxyEngine on
    SSLProxyVerify require
    SSLProxyCheckPeerName on
    SSLProxyCheckPeerExpire on

    ProxyPass / https://backend.example.com:1234/
    ProxyPassReverse / https://backend.example.com:1234/
</VirtualHost>

In comparison, client --> https://example.net/ --> https://198.51.100.3:5678/ without any certificate validations:

<VirtualHost *:443>
    ServerName example.net

    SSLEngine on
    SSLCertificateFile /etc/letsencrypt/live/example.net/fullchain.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/example.net/privkey.pem

    SSLProxyEngine on
    SSLProxyVerify none
    SSLProxyCheckPeerName off
    SSLProxyCheckPeerExpire off

    ProxyPass / https://198.51.100.3:5678/
    ProxyPassReverse / https://198.51.100.3:5678/
</VirtualHost>