Modifying LogFormat in Apache

Solution 1:

The IfModule directive is to take the configuration only if the module was loaded. To check which modules are loaded you can use

• httpd -M -f path-to-config-file using linux
• and httpd -t -D DUMP_MODULES using windows

Example

[root@apachesrv bin]# httpd -M -f conf/httpd-vserver.conf
Loaded Modules:
 core_module (static)
 ...
 log_config_module (shared)
 ...
 proxy_http_module (shared)
 schema_module (shared)
Syntax OK

In this case you can see I am using the log_config_module so it will take (on my case) the config

<IfModule log_config_module>
  LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
  LogFormat "%h %l %u %t \"%r\" %>s %b" common

  CustomLog "logs/access_log" common

  <IfModule logio_module>
    LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio    
  </IfModule>    
</IfModule>

In order to catch the information you need you need to configure a log with something like:

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" \"%{X-Forwarded-For}i\"" combinedcustomized

And then change your access log to:

CustomLog logs/access.log combinedcustomized

EDIT:

On the apache doc you have the list of available parameters to log http://httpd.apache.org/docs/2.4/mod/mod_log_config.html