Sonatype Nexus Apache reverse proxy - Service unavaliable

In order to execute Sonatype Nexus behind an Apache httpd poxy, you can follow this instrunctions: http://books.sonatype.com/nexus-book/reference/install-sect-proxy.html

But you may get an apache error of "service unavaliable". Te solution is executing de followning command:

/usr/sbin/setsebool -P httpd_can_network_connect true