Nagios Support Forum

Email Notifications are not going through all of the sudden. The current version of Nagios Core i'm using is version 3.5.1 (older version ). i noticed an old post few years back with similar issue but it was eventually resolved. im wondering if someone can explain to me the resolution steps solving this issue.

https://support.nagios.com/forum/viewto ... =7&t=30994

It looks like that person had issues with their notification command, as well as their Postfix configuration.

Here are some relevant links on the Postfix issue.
http://www.postfix.org/ADDRESS_REWRITING_README.html
https://www.cyberciti.biz/tips/howto-po ... dress.html

But the issue of email just not getting sent out seems pretty broad. It might be worth doing some additional troubleshooting before jumping into the deep end with Postfix. When an email should be sent out, do you see anything in the system's mail log, or system log?

I did some testing using Postfix own sendmail setup. I was able to received the email with no issue. However, when i try to trigger a downtime within Nagios I noticed the maillog file with the following info "to=<[email protected]>" and "from=<[email protected]>" which will explain why i am not receiving these notifications. How do i change the from address?

If this is for an Icinga system, your best bet would be to run this issue past their support.

from maillog...

Oct 22 08:56:05 nagios-01 postfix/pickup[114943]: D5BC0C447B: uid=496 from=<icinga>
Oct 22 08:56:05 nagios-01 postfix/cleanup[8078]: D5BC0C447B: message-id=<[email protected]>
Oct 22 08:56:05 nagios-01 postfix/qmgr[94257]: D5BC0C447B: from=<[email protected]>, size=790, nrcpt=1 (queue active)
Oct 22 08:56:05 nagios-01 postfix/smtp[8080]: D5BC0C447B: to=<[email protected]>, orig_to=<icinga@localhost>, relay=FQDN.SMTP[x.x.x.x][/color][/color]:25, delay=0.11, delays=0.05/0.01/0/0.04, dsn=2.6.0, status=sent (250 2.6.0 <[email protected]> Queued mail for delivery)
Oct 22 08:56:05 nagios-01 postfix/qmgr[94257]: D5BC0C447B: removed
Oct 22 09:00:04 nagios-01 postfix/pickup[114943]: 5CE71C447B: uid=0 from=<root>
Oct 22 09:00:04 nagios-01 postfix/cleanup[8762]: 5CE71C447B: message-id=<[email protected]>
Oct 22 09:00:04 nagios-01 postfix/qmgr[94257]: 5CE71C447B: from=<[email protected]>, size=732, nrcpt=1 (queue active)
Oct 22 09:00:04 nagios-01 postfix/smtp[8764]: 5CE71C447B: to=<[email protected]>, orig_to=<root>, relay=FQDN.SMTP[x.x.x.x]:25, delay=2.5, delays=2.4/0.01/0/0.05, dsn=2.6.0, status=sent (250 2.6.0 <[email protected]> Queued mail for delivery)
Oct 22 09:00:04 nagios-01 postfix/qmgr[94257]: 5CE71C447B: removed

I'm sorry, we cannot help with icinga servers.