Can anyone clarify this line from http logs?

[glennzo]

75.179.146.179 - - [12/Apr/2012:15:57:21 -0400] "HEAD /manager/status HTTP/1.1" 404 - "-" "Java/1.6.0_25"

What is the point, or the meaning, of this? Anyone?

[aleph]

Some bot trying to profile your server's Tomcat installation?

[glennzo]

Very likely. I seem to get a lot of them, but what's with the dashes and quotes? Does that have a significant meaning in the http world?

[aleph]

Dashes are missing data in the log fields. The quotes usually are used to encapsulate a field that can have whitespace breaks or special characters, such as the request line (whitespace between the method and resource location), the Referer and the user-agent.

I assume this log format is the "Combined Log Format". If I remembered correctly that's what I saw on Fedora's default Apache installations. But I haven't touched Apache for a while and I could be wrong...
The Combined format looks like this:

host identity-info username time "request" status size "Referer" "user-agent"

In your case, the identity info, username, size and Referer fields are empty.

[glennzo]

Thanks for clarifying Aleph. There are a lot of requests from bots and script kiddies. Some of them 3-4 times a day or 3-4 times in succession. Nothing that I'm overly concerned with but I am trying to gain a better understanding of what is actually going on as I read the logs.

[aleph]

You're welcome Glenn As you said, shouldn't be much a worry

[Doug G]

The apache log format is configurable. http://httpd.apache.org/docs/2.0/mod...og_config.html

You can check the LogFormat setting in your httpd.conf or vhost files to see exactly how your server logs stuff.