## Index → Modules → Loggers

### Logger: Combined

This logger produces logfiles that conform to the Combined Log Format. It is commonly used by many programs, being the standard format used by Apache. This is a de facto standard and is the most widely used. As such, you are encouraged to use it.

This format is exactly the same as the Common Log Format, with two extra fields.

    host rfc931 username date:time request statuscode bytes referer user_agent

Here is an example:

::ffff:127.0.0.1 - - [11/Aug/2008:16:17:58 +0000] "GET /index.html HTTP/1.1" 200 2633 "-" "Mozilla/5.0 (X11; U; Linux i686; es-ES; rv:1.9.0.1) Gecko/2008072820 Firefox/3.0.1"

The description of the additional fields follows. Refer to the Common Log Format documentation for information about the rest of the fields.

referer ("-")

  This is the "Referer" HTTP request header. This indicates the URL which linked the user to your site (as reported by the client). In this case it is empty because no Referer exists (i.e. it is a direct hit).

user_agent ("Mozilla/5.0 (X11; U; Linux i686; es-ES; rv:1.9.0.1) Gecko/2008072820 Firefox/3.0.1")

  The User-Agent HTTP request header. This is the information reported by the client about itself.