Hi,
New to Nagios here, and this doesn't make much sense to me. I followed quick start guides for Fedora, and configuring a windows server to test Nagios out on one server.
I initially had it set up and received notifications from localhost. I then added the windows server in the proper config file and was still able to receivie notification.
Once I had set up the ability to access the web panel from a remote machine, the notifications stopped. The nagios log is showing notifications being sent to sendmail, /var/log/maillog is showing unable to qualify my own domain name.
Now this is a fresh install of Fedora 16, simply installed the Nagios packages following the quickstart guides and set up the apache server to run. I have done no other config changes to sendmail or any other service.