How can I rewrite a Website(domain) or Subdomain to ispconfig.paneladress:8080 ?

Using example domain names/ports, what exactly are you trying to accomplish? Eg. make https://cp.domain.com/ function as the ispconfig control panel, which is actually running on port 8080 (so the url looks nicer, without just redirecting to the port 8080 url)?

 

There is no manual configuration in the apache config files required. Just add a subdomain "cp" to the website domain.tld and put the target URL e.g. https://domain.tld:8080 in the redirect field of this subdomain.

 

That redirect does work function-wise; if you want to keep the nicer https://cp.domain.tld/ url displaying then instead of redirecting you would proxy the connection on the back end. There's a more comprehensive example at https://www.howtoforge.com/community/threads/3-1-update-reverse-proxypass-apache.73210/#post-344465, but the parts you'd need for just the 'cp' subdomain are this (using debian jessie file locations/commands):

Enable proxy module and create a server-wide apache .conf file:

Code:

# cat >/etc/apache2/conf-available/proxy_requests_off.conf <<EOF
<IfModule mod_proxy.c>
    ProxyRequests Off
</IfModule>
EOF

# a2enmod proxy
# a2enmod proxy_http
# a2enconf proxy_requests_off

And put this in the apache directives for the cp.domain.tld website:

Code:

    <If "%{HTTPS} == 'on'">
        SSLProxyEngine on
        <IfModule mod_proxy.c>
            ProxyRequests Off
            ProxyPreserveHost On
            ProxyPass /webmail "!"
            ProxyPass /roundcube "!"
            ProxyPass /squirrelmail "!"
            ProxyPass /phpmyadmin "!"
            ProxyPass / https://127.0.0.1:8080/
            ProxyPassReverse / https://127.0.0.1:8080/
        </IfModule>
    </IfModule>

Note the above is untested (the example in that other post I linked above is tested code). That should also let you easily use a letsencrypt certificate for cp.domain.tld by enabling the checkbox for it.

I've been planning to write somthing along those lines into a little howto here on howtoforge, as it's a nice solution for resellers to access a shared control panel through their own domain name, though I don't have an equivalent nginx example to go with it.