Hi, 

Have you try connecting to your mail server via Telnet?

Maybe is a server/firewall/proxy configuration error and not a Centreon issue...

Thanks for your answer.

I can’t connect to it with Telnet, but I can’t neither on my LibreNMS and I receive mails from it.
I’ll try to find how it works.

Does the test work? change as needed

echo "Test" | mail -s "Test" user@isp.com

from:

https://docs.centreon.com/docs/administration/postfix/

Logs I put in the first message where from :

echo "Test mail from postfix" | mail -s "Test Postfix" @mail
 

@StanislasR in that case looks like the “Connection refused” issue needs to be resolved

Yes, I’ll see but that’s probably a firewall rule issue but I currently can’t see that.

Mail is working now, the firewall rule for smtp was wrong.

Now, I’ve another issue, I have mail notification when hosts are up.

I’ve found on the Internet that it often happen and it’s a configuration issue but I can’t find what is wrong.

My ping check configuration :

$USER1$/check_ping -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -n $ARG3$

ARG1 : 300,50%
ARG2 : 500,100%
ARG3 : 5

And I have this configuration on my hosts :

!300,50%!500,100%!5

Something is wrong ?

Thanks and have a nice day.

Ok, problem solved, it was a mistake from me.

I had true mail alerts but the following parameter had not been set.

So I had host up alert for a real CPU/RAM threshold exceeded.

I changed interval between mail alerts too because it was flooding my mailbox.