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From: Doug Hardie <bc979@lafn.org>
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Subject: System Calls that do DNS
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Date: Mon, 3 Jun 2013 19:57:07 -0700
To: freebsd-questions <freebsd-questions@freebsd.org>
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I have an unusual situation.  A program is doing a DNS lookup and often =
the IP address has no reverse DNS entries.  As a result the program =
hangs for several timeouts.  The call is not being made directly in its =
code, but is occurring in a system call.  There are no specific calls to =
DNS, its something else doing it.  I have been trying to track down =
which system call is doing it, but without success so far.  I have tried =
syslog calls around each of the system calls I thought might be the =
culprit, but my guessing is not very good.  How can I identify the =
system call that is calling DNS?  If I can find it, I hopefully can find =
another way to do whatever it does that does not involve a reverse DNS =
lookup.