Setting up SMTP for Proxmox Notification Emails

Background

When I set up our home server, I wanted at least enough observability to know if things were running smoothly or quietly catching fire 🔥 Luckily, Proxmox has an easy way to add email notifications, which is a simple way to accomplish a baseline of observability. I was able to set up our installation of Proxmox to send alerts through Protonmail, without storing my actual account password on the server. That way, if the box gets compromised, I can simply revoke the SMTP token instead of being locked out of email entirely.

Email Notifications on Proxmox with Protonmail

Out of the box, Proxmox provides us a very basic level of observability, e.g.:

"storage replication failures, node fencing, finished/failed backups and other events" - Proxmox Notifications Docs

If you're not using Protonmail, then some of the details that follow will be different based on your email provider, but the gist should be the same.

Step 1: Get SMTP Credentials

Go to Settings → All Settings → IMAP/SMTP, and click Generate Token.

Name the token something memorable. For example, I went with "Anton (Proxmox)" since our server is named Anton and this token is for Proxmox specifically.

Save the credentials somewhere safe, or just keep the tab open while you set up Proxmox.

Step 2: Add a Notification Target

Following the guide for Proxmox Notifications, add an SMTP Notification Target for Protonmail.

Option A: Using the Web UI

Head into the Proxmox web UI and follow the Proxmox Notifications guide. Add a new SMTP Notification Target:

• Name: something like protonmail-smtp
• Encryption: STARTTLS
• Username / Password: use the Protonmail email address and generated token
• Recipient(s): root@pam

If editing the files directly, this will all mostly be the same, just slightly different names/syntax.

Option B: Editing Config Files Manually

You can also configure everything via plain text. I reach for vi but use whatever text editor you like. E.g.:

vi /etc/pve/notifications.cfg

Here’s a sample SMTP target block:

smtp: protonmail-smtp
        comment Sends mails to root@pam's email address as <FROM_ADDRESS>
        from-address <FROM_ADDRESS>
        mailto-user root@pam
        mode starttls
        server smtp.protonmail.ch
        username <FROM_ADDRESS>

Credentials will be stored in /etc/pve/priv/notifications.cfg. E.g.:

smtp: protonmail-smtp
        password <SMTP_TOKEN>

Make sure to replace <FROM_ADDRESS> and <SMTP_TOKEN> with your actual values.

Step 3: Add a Notification Matcher

Option A: Using the Web UI

Add a new matcher like:

• Name: protonmail-matcher
• Description: "Route all notifications through Protonmail"
• Match Rules: match all
• Target: Your protonmail-smtp target

Option B: Editing Config Files Manually

In /etc/pve/notifications.cfg, add:

matcher: protonmail-matcher
        comment Route all notifications through Protonmail
        mode all
        target protonmail-smtp

This matcher routes all notifications to your Protonmail SMTP target. If you want more granular control, you can match based on severity or class.

Step 4: Test It

Now disable the default built-in targets and matchers (mail-to-root, default-matcher), either in the GUI or by adding disable true to their sections in the config file.

Then test your SMTP target from the GUI.

If everything’s working:

• ✅ No errors are thrown
• 📤 The message shows up in your Protonmail Sent folder
• 📨 You receive the test email in your root@pam user's inbox

Conclusion

Setting up SMTP notifications in Proxmox isn't particularly difficult, but hopefully this all-in-one guide is helpful to avoid needing to search for all the disparate information to get it set up.

With email alerts enabled, you’re no longer dependent on smoke signals from your box or frustrated family members telling you something’s broken, since they seem to think your home server comes with a 5 9's SLA.

In a future post, I'll cover how to set up more granular observability and alarming using Prometheus and Grafana, which can also leverage SMTP tokens for emails.