If you get the following error (“CHECK_NRPE: Error – Could not complete SSL handshake.“) when trying to connect to a remote NRPE (nagios) setup you should check on the NRPE machine that check_nrpe client IP is in the list.
In the /etc/nagios/nrpe.cfg configuration file.
For some reason the mail log was showing lots of:
Sep 23 09:40:03 hostname qmail: 1253695203.637058 alert: cannot start: unable to open mutex
Sep 23 10:32:16 hostname qmail: 1253698336.515510 alert: cannot start: unable to open mutex
Sep 23 10:32:21 hostname qmail: 1253698341.425333 alert: cannot start: unable to open mutex
and qmail was not working properly.
It turns out that for some reason /var/qmail/queue/lock/ was missing along with the file /var/qmail/queue/lock/sendmutex. Had to recreate these with:
[root@hostname ~]# mkdir /var/qmail/queue/lock/
[root@hostname ~]# chown qmailq:qmail /var/qmail/queue/lock/
[root@hostname ~]# touch /var/qmail/queue/lock/sendmutex
[root@hostname ~]# chown qmails:qmail /var/qmail/queue/lock/sendmutex
Then qmail would start fine.