PLUTO uses error codes and short explanations to categorize the result of every test. Most of these codes and messages are the familiar HTTP status codes and messages, however we added a few extra ones for our purposes. Below is a list of all the codes and messages you might find in an error report or summary that you receive from PLUTO. You can also find a short explanation of the likely cause of the error.

Notes: A few errors in the 10X range are normal. We see typically less than one percent. The error types 104 and 105 may require your immediate attention. Also, you should not see any 500 errors; they indicate problems with your server scripts (file permission, return header, ...). Some of the error codes in the 40X range may be something that you do want to test for explicitly as they are related to access privileges.

000 No Test

The computer running PLUTO apparently lost its connection to the Internet. Most likely everything is ok on your end, however PLUTO was unable to check.

101 Name Server Error

This may be a problem on your end. PLUTO was unable to get your IP address from the name of your computer. PLUTO tried twice and was successful in looking up a different computer in between. Check if there was a problem with your name server.

104 Connection Error

You surely had those cases when you tried to access a web page and nothing happened for a long time and then you get a message that the connection was refused. This is that case. Again, PLUTO tried twice and established a connection with someone else in between. The problem was on your server's end or on the internet between us and you. Your computer may have been down or lost its connection to the Internet, possibly just because your corner of the internet was too busy.

105 Connection Timed Out

For a browser the symptoms are similar to the previous error: a long wait and no response. In this case however, a connection was established and hence your computer must be up. The server program did not respond to PLUTO's request before a time-out (default 30 seconds) expired. You should check your server daemon.

200 Ok

No Problem - a happy browser.

302 Found

This is also a good response. The server found the data you want, however they reside under a different URL. Transparently to you, a browser would go and fetch the document containing the requested data.

400 Bad Request

If you ever get this one then there is probably something wrong with the way PLUTO was invoked. (some crazy thing instead of the filename?) From the standpoint of determining if your server is operating this is not really a bad response since it proves at least that it's answering. Check how PLUTO is invoked.

401 Unauthorized

You requested PLUTO to check on a document that requires authorization. If you wanted to know if your access control mechanism works then everything is fine. Otherwise you should probably monitor a different file on your server.

403 Forbidden

Similar to 401. The difference between the two is that authorization will not help to retrieve this document. You should get this response if you protected a document intentionally. If you do mean to distribute the file your file access privileges are probably wrong. (run chmod.)

404 Not Found

The document PLUTO was instructed to get just isn't there. Did you move it, delete it? Time to check!

500 Internal Error

This error typically comes up in connection with CGI scripts. The program that is supposed to generate the data to be returned didn't make it for some reason. Are you returning the Content-Type header from within your script? You'll have to check your installation.

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