Description

User sees  quite a lot of SMTP failure messages on the Apstra server show tech output (inside show tech > controller_vm_info/logs/syslog),

Jul 3 06:25:08 aos-server nullmailer-send[1133]: Trigger pulled.
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Rescanning queue.
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery, 15 message(s) in queue.
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery: host: mail protocol: smtp file: 1719469509.20110
Jul 3 06:25:08 aos-server nullmailer-send[1133]: From: <> to: <root@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Message-Id: <1719469509.075225.20111.nullmailer@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: smtp: Failed: Connect failed
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Sending failed: Host not found
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery: host: mail protocol: smtp file: 1719987908.9464
Jul 3 06:25:08 aos-server nullmailer-send[1133]: From: <root@aos-server> to: <root@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Message-Id: <1719987908.487483.9461.nullmailer@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: smtp: Failed: Connect failed
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Sending failed: Host not found
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery: host: mail protocol: smtp file: 1719642308.27355
Jul 3 06:25:08 aos-server nullmailer-send[1133]: From: <root@aos-server> to: <root@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Message-Id: <1719642308.926692.27348.nullmailer@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: smtp: Failed: Connect failed
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Sending failed: Host not found
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery: host: mail protocol: smtp file: 1719901508.22110
Jul 3 06:25:08 aos-server nullmailer-send[1133]: From: <root@aos-server> to: <root@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Message-Id: <1719901508.960244.22109.nullmailer@aos-server>
Jul 3 06:25:08 aos-server nullmailer-send[1133]: smtp: Failed: Connect failed
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Sending failed: Host not found
Jul 3 06:25:08 aos-server nullmailer-send[1133]: Starting delivery: host: mail protocol: smtp file: 1719815108.2074

Symptoms

By default the mailer daemon isn't configured for any particular MTA. User can configure it to deliver alerts if they have a MTA.

Solution

User can follow the below steps to setup nullmailer to discard any messages that are generated by the vm and to clear the queue.


sudo ln -s /bin/true /usr/lib/nullmailer/

sudo echo "localhost true" > /etc/nullmailer/remotes

sudo touch /var/spool/nullmailer/trigger

 

After executing the above steps user will no longer see lots of log messages regarding failed mail. Post this execution user can crosscheck with the below CL

root@aos-server:~# tail -f /var/log/syslog

Modification History

reviewed and validated 

Modified categories from all to Apstra intent based on 2025:01:28

Removed partner assistance from categories on 2025:01:29