I ran into a bug in the way check_smtp handles responses. I reported it to the nagiosplug-help mailing list and received the following patch that fixes the problem: http://sourceforge.net/mailarchive/message.php?msg_name=20070804032532.GP9031796%40CIS.FU-Berlin.DE Would it be possible to go ahead and update the Fedora 7 nagios-plugins package with this patch until a new upstream version is released with it included?
nagios-plugins-1.4.8-3.fc7 has been pushed to the Fedora 7 stable repository. If problems still persist, please make note of it in this bug report.
Thanks! That has fixed the problem.