Understanding Apache Access Log

Combined Log Format

Whevever someone accesses your website it records a Combined Log Format. It is in the format as follows.

LogFormat “%h %l %u %t \”%r\” %>s %b \”%{Referer}i\” \”%{User-agent}i\”” combined

1. %h is the remote host (ie the client IP)
2. %l is the identity of the user determined by identd (not usually used since not reliable)
3. %u is the user name determined by HTTP authentication
4. %t is the time the server finished processing the request.
5. %r is the request line from the client. (“GET / HTTP/1.0”)
6. %>s is the status code sent from the server to the client (200, 404 etc.)
7. %b is the size of the response to the client (in bytes)
8. Referer Referer is the page that linked to this URL.
9. User-agent User-agent is the browser identification string.