Invalid command 'RPAFenable', perhaps misspelled or defined by a module not included in the server configuration

[Mauro Delazeri]

AH00526: Syntax error on line 2 of /etc/apache2/mods-enabled/rpaf.conf:
Invalid command 'RPAFenable', perhaps misspelled or defined by a module not included in the server configuration
Action 'configtest' failed.
The Apache error log may have more information.

<IfModule rpaf_module>
    RPAFenable On

    # When enabled, take the incoming X-Host header and
    # update the virtualhost settings accordingly:
    RPAFsethostname On

    # Define which IP's are your frontend proxies that sends
    # the correct X-Forwarded-For headers:
    RPAFproxy_ips 127.0.0.1 ::1

    # Change the header name to parse from the default
    # X-Forwarded-For to something of your choice:
# RPAFheader X-Real-IP
</IfModule>

should be

<IfModule mod_rpaf.c>
    RPAFenable On

    # When enabled, take the incoming X-Host header and
    # update the virtualhost settings accordingly:
    RPAFsethostname On

    # Define which IP's are your frontend proxies that sends
    # the correct X-Forwarded-For headers:
    RPAFproxy_ips 127.0.0.1 ::1

    # Change the header name to parse from the default
    # X-Forwarded-For to something of your choice:
# RPAFheader X-Real-IP
</IfModule>