Apache 500 Error due to User Agent?

问题

I am currently getting 500 errors from Apache using a alarming probe shell script that has been provided to myself.

Unfortunately I have not been able to get to the bottom of why the script generates a 500 error when attempting to access content locally on the server but using other methods like wget and telnet works fine.

The following are the Apache access log entries for each of the attempts:

Using Wget

127.0.0.1 - "" [19/Mar/2013:14:31:44 +1100] "GET /index.html HTTP/1.1" 200 1635 "-" "Wget/1.13.3" "-"

Using Telnet

127.0.0.1 - "" [20/Mar/2013:13:12:11 +1100] "GET /index.html HTTP/1.1" 200 1635 "-" "-" "-"

Using the Probe Scripts

127.0.0.1 - -  [19/Mar/2013:14:33:56 +1100] "GET /index.html HTTP/1.1" 500 -    "-" "" "-"

The only difference I can see is that the probe has a - instead of a "" in the user agent (3rd item) which either way tells me it wasn't passed in any of the instances (as this is expected since there is no authentication).

I've bumped up the logging for everything in Apache and can't figure out what is amiss. There is no processing involved, it's a static file, and I have attempted with other file types too, like images to no avail.

Does anyone have any ideas or has seen something similar?

Thanks, Tony

来源：https://stackoverflow.com/questions/15514110/apache-500-error-due-to-user-agent