With apache it is possible to have a reverse proxy with AJP instead of http. With the use of mod_proxy_ajp it is very simple to set up and faster than just plain http protocol
<VirtualHost *:80>
ServerName jenkins
DocumentRoot "/mario/Apache22/htdocs"
<Directory "/mario/Apache22/htdocs">
Options Indexes Includes FollowSymLinks
AllowOverride All
Order Allow,Deny
Allow from all
Deny from none
</Directory>
<Location />
ProxyPass ajp://localhost:8009/
ProxyPassReverse ajp://localhost:8009/
</Location>
SetEnv vhostname jenkins
Header add X-Server-Name %{vhostname}e
</virtualhost>
Than start the backend server, in this case only with AJP and listen only on localhost
java -jar jenkins.war --httpPort=-1 --ajp13ListenAddress=127.0.0.1