Check/monitor SMTP server for TLS and SSL connections

Written by - 0 comments

Published on - Listed in Linux Nagios Internet Mail Monitoring


There are a couple of possibilities how to monitor SSL over SMTP and TLS over SMTP, I'll show two of them here.

With Nagios plugins

The Nagios plugins come with check_smtp for normal smtp connections and tls and check_ssmtp for ssl on smtp. check_ssmtp is using check_tcp in the background.

Check TLS over SMTP running on port 587 on remote server:

./check_smtp -H remote.example.com -p 587 -S
SMTP OK - 0.329 sec. response time|time=0.328936s;;;0.000000

Check SSL over SMTP running on port 465 on remote server:

./check_ssmtp -H remote.example.com -p 465 -S
SSMTP OK - 0.171 second response time on port 465 [220 remote.example.com Postfix ready]|time=0.171020s;;;0.000000;10.000000

 

With openssl command

Another very handy way is to use openssl as a command. I actually didn't know it was possible to use openssl as a connection "client" until I read this post today.

Check TLS over SMTP running on port 587 on remote server:

openssl s_client -connect remote.example.com:587 -starttls smtp

Check SSL over SMTP running on port 465 on remote server:

openssl s_client -connect remote.example.com:465

Both commands will return the actual TLS/SSL server certificates and you'll arrive at the "mail prompt" which then usually starts with "ehlo" or "helo". From here on you can check to send an e-mail or check for the mail return codes.


Add a comment

Show form to leave a comment

Comments (newest first)

No comments yet.

RSS feed

Blog Tags:

  AWS   Android   Ansible   Apache   Apple   Atlassian   BSD   Backup   Bash   Bluecoat   CMS   Chef   Cloud   Coding   Consul   Containers   CouchDB   DB   DNS   Database   Databases   Docker   ELK   Elasticsearch   Filebeat   FreeBSD   Galera   Git   GlusterFS   Grafana   Graphics   HAProxy   HTML   Hacks   Hardware   Icinga   Icingaweb   Icingaweb2   Influx   Internet   Java   KVM   Kibana   Kodi   Kubernetes   LVM   LXC   Linux   Logstash   Mac   Macintosh   Mail   MariaDB   Minio   MongoDB   Monitoring   Multimedia   MySQL   NFS   Nagios   Network   Nginx   OSSEC   OTRS   Office   PGSQL   PHP   Perl   Personal   PostgreSQL   Postgres   PowerDNS   Proxmox   Proxy   Python   Rancher   Rant   Redis   Roundcube   SSL   Samba   Seafile   Security   Shell   SmartOS   Solaris   Surveillance   Systemd   TLS   Tomcat   Ubuntu   Unix   VMWare   VMware   Varnish   Virtualization   Windows   Wireless   Wordpress   Wyse   ZFS   Zoneminder   


Update cookies preferences