This is a log format defined by the W3C which can contain a variable amount of information. The format is defined at http://www.w3.org/TR/WD-logfile.html.
This log format uses a header to specify the order of the fields present in the log file.
Lire can use the following fields of the format:
          date,
          time,
          c-ip,
          c-dns,
          cs-uri,
          cs-method,
          sc-bytes,
          sc-status,
          cs(User-Agent),
          cs(Referer),
          cs-uri-stem
          and
          cs-username.
          The other fields will be ignored.