<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7654.12"> <TITLE>Problem with check_mailq and check_smtp plugins</TITLE> </HEAD> <BODY>  Hi there -- I recently rebuilt an e-mail server from scratch, and part of the process was restoring from disk backup the nrpe directory that was one the original server. The original server ran on the Fedora Core 7 32-bit distribution, while the new one is running on the CentOS 5.6 64-bit operating system. The version of nrpe that was restored to the new server is 2.6, while that of the plugins is the 1.4.5 release. The Nagios server is version 3.1.2 running on a CentOS 5.3 32-bit distribution. Two of the plugins that I use to monitor the e-mail portion of the server, check_mailq and check_smtp, do not appear to be working. The error messages that appear on the Nagios server web interface are shown below: <A HREF="http://romonitor/nagios/cgi-bin/extinfo.cgi?type=2&host=hadron&service=Check+Sendmail+Queue">Check Sendmail Queue</A> (check_mailq) CRITICAL 04-15-2011 15:41:36 0d 3h 7m 54s 4/4 CRITICAL: Error code 78 returned from /usr/bin/mailq <A HREF="http://romonitor/nagios/cgi-bin/extinfo.cgi?type=2&host=hadron&service=Check+Sendmail+Server">Check Sendmail Server</A> (check_smtp) CRITICAL 04-15-2011 15:41:36 0d 3h 7m 54s 4/4 Connection refused I tried running both locally on the e-mail server, and while check_mailq appears to work based on the output shown below: /usr/local/nrpe/libexec/check_mailq -w 30 -c 40 -M sendmail OK: mailq is empty|unsent=0;30;40;0 the check_smtp plugin has the following output: Connection refused SMTP CRITICAL - 0.059 sec. response time|time=0.058524s;;;0.000000 Other plugins that I run on the server, i.e: check_disk, check_zombie_procs, check_imap, are all running without issue. Does anyone have insight into what is going on, and how it can be corrected? Thanks. The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.</BODY> </HTML>