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Title:Debugging "CHECK_NRPE: Error - Could not complete SSL handshake" errors
FAQ ID:F0191
Submitted By:Greg Haygood, Ethan Galstad and Others 
Last Updated:11/03/2004


When attempting to use the check_nrpe plugin, the following error message is printed:

CHECK_NRPE: Error - Could not complete SSL handshake



This error message could be due to several problems:

  1. Different versions. Make sure you are using the same version of the check_nrpe plugin and the NRPE daemon. Newer versions of NRPE are usually not backward compatible with older versions.
  2. SSL is disabled. Make sure both the NRPE daemon and the check_nrpe plugin were compiled with SSL support and that neither are being run without SSL support (using command line switches).
  3. Incorrect file permissions. Make sure the NRPE config file (nrpe.cfg) is readable by the user (i.e. nagios) that executes the NRPE binary from inetd/xinetd.
  4. Pseudo-random device files are not readable. Greg Haygood noted the following... "After wringing my hair out and digging around with truss, I figured out the problem on my Solaris 8 boxen. The files /devices/pseudo/random* (linked through /dev/*random, and provided by Sun patch 112438) were not readable by the nagios user I use to launch NRPE. Making the character devices world-readable solved it."
  5. Unallowed address. If you're running the NRPE daemon under xinetd, make sure that you have a line in the xinetd config file that say "only_from =", where is the IP address that you're connected to the NRPE daemon from.

Dave van Nierop added that "Fortunately, for HPUX 11.i (11.11) and later Nagios users, HP now supports /dev/random and /dev/urandom via a kernel loadable module. Prior to running the NRPE 2.0 configure script, you will need to download this program from Installation does require a server reboot. For detailed information, consult


Keywords:check_nrpe ssl handshake solaris sun hp-ux