How to Set Up Nagios XI Email Notifications with Yahoo Mail SMTP

This step‑by‑step guide shows how to send Nagios XI notification through Yahoo Mail using secure SMTP with TLS and a Yahoo app password. You’ll set up account security, configure SMTP in Nagios XI, verify with test messages, and troubleshoot common errors.

Prerequisites

1. Yahoo account with 2‑step verification enabled.
2. Yahoo App Password: A 16-character code generated specifically for “Nagios XI.”
3. Nagios XI Admin Access: Ensure the XI server has outbound network access to smtp.mail.yahoo.com on ports 587 and/or 465.
4. Accurate time/NTP on the XI host to avoid TLS/certificate errors.

Step 1: Enable Two-Step Verification and Generate a Yahoo App Password

1. Log into your Yahoo account at Yahoo Account Security.
2. Navigate to Two-step verification and enable it.
3. Under App passwords, click Generate app password, enter “Nagios XI” as the label, and click Create.
4. Copy the 16-character password displayed and store it securely for use in Nagios XI. Ensure no extra spaces are copied, and do not use your regular Yahoo account password.

Tip: If “App passwords” isn’t shown, confirm 2-step is on, sign out/in, and use the main Yahoo site (not carrier portals). If your account type doesn’t support app passwords, use an SMTP relay instead.

Step 2: Configure SMTP Settings in Nagios XI

1. Log into Nagios XI as an administrator and navigate to Admin → System Config → Email Settings.
2. Update the Send Mail From field from the default root@localhost to Nagios Alerts <[email protected]> (replace with your actual Yahoo email address).
3. Select Mail Method: SMTP.
4. Configure the following SMTP Settings:
   • Host: smtp.mail.yahoo.com
   • Port: 587
   • Security: TLS (recommended; SSL on port 465 is also supported)
   • Username: Your full Yahoo email address (e.g., [email protected])
   • Password: The 16-character app password from Step 1
5. Click Update Settings.

Step 3: Update User Email in Account Settings

1. In Nagios XI, click the user icon in the top-right corner and select Account Settings.
2. Update the Email Address field from the default root@localhost to the email address where you want to receive notifications (e.g., [email protected] or another preferred email).
3. Enter your current Nagios XI password to authenticate the change.
4. Click Update Settings to save the email address.

Step 4: Send a Test Email

1. Return to Admin → System Config → Email Settings.

2. Click Send A Test Email to verify the SMTP configuration.

3. Verify that the test email arrives in the designated inbox. If it’s not there, check the spam or junk folder.

Step 5: Test Notifications with a Real Alert

1. Assign the Yahoo-backed contact to a test host or service in Nagios XI.
2. Trigger a test alert by forcing a soft problem state or using the Send Custom Notification feature.
3. Verify that the alert email arrives in the designated inbox. Check the spam or junk folder if it does not appear.

Troubleshooting

Symptom	Likely Cause	Solution
535 Authentication failed	Using regular Yahoo password	Use the 16-character app password. Regenerate if necessary, ensuring no extra spaces.
Connection timeouts	Firewall blocking ports 587/465	Allow outbound TCP 587 and/or 465 to smtp.mail.yahoo.com.
TLS handshake or certificate errors	Outdated OpenSSL/CA bundle or time sync	Update CA certificates, verify NTP sync, and retry with TLS on port 587.
Test email works, contacts get nothing	Legacy sendmail commands in use	Switch affected contacts to XI PHPMailer notification commands.
Emails land in spam	Mismatched From domain or poor content	Use your Yahoo address in From, ensure meaningful subject/body, avoid URL-only emails.

Conclusion

Yahoo Mail SMTP gives Nagios XI reliable, secure alerts. Enable two-step verification and create an app password. Configure TLS on port 587 with the correct Yahoo SMTP host.

For further support, visit the Nagios Support Forum or the Nagios Knowledgebase.