"We can talk," said the Tiger-lily, "when there's anybody worth talking to."
One of the tools in your troubleshooting toolchest is the name server's debugging output. As long as your name server has been compiled with DEBUG defined, you can get query-by-query reports of its internal operation. The messages you get are often quite cryptic; they were meant for someone who has the source code to follow. We'll explain some of the debugging output in this chapter. Our goal is to cover just enough for you to follow what the name server is doing; we aren't trying to supply an exhaustive compilation of debugging messages.
As you read through the explanations here, think back to material covered in earlier chapters. Seeing this information again, in another context, should help you understand more fully how a name server works.
BIND 8 and 9 have a whopping 99 debug levels, but most of the debugging messages are logged at just a few of those levels. We'll look at those now.
Keep in mind that this is debugging information -- it was used by the authors of BIND to debug the code, so it is not as readable as you might like. You can use it to figure out why the name server isn't doing what you think it should be or just to learn how the name server operates -- but don't expect nicely designed, carefully formatted output.
|12.9. Using dig||13.2. Turning On Debugging|
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