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Mail Host Alerts


Our Mail host alerts feature ensures you stay informed about the status of your mail server. In the event of chronic delivery failure or deferring mail, the system sends an alert to your third-party email address or SMS gateway email address.

Upon recovery, the system will also send a follow-up "Mail host ok" alert and, for extended outages (60 minutes or longer), automatically flush the mail queue.

The Mail host alerts feature is included with our Reseller and Enterprise plans.

Smart monitoring

Following is a more in-depth look at our intuitive mail host monitoring features.

  • Dynamic alert time threshold - The sensitivity of the monitoring system is calculated on a per-domain basis. Domains with consistent inbound mail flow will be alerted within 5 minutes of an outage, while domains that receive very little mail will not be alerted for up to 15 minutes (to avoid false alerts).
  • Courtesy mail-queue flush after extended outage - If your mail server is offline for at least 60 minutes, our system will automatically flush the mail queue as soon as when you're back online. For shorter outages, the automatic redelivery attempts should be sufficient but can also do a manual flush mail queue, as needed.
  • Account-wide defaults with domain-level exceptions - Use the "Account settings" tab to control the default configuration for all domains on your account. The "Domain settings" tab allows you to disable alerts for individual domains or send the alerts to an alternate email address.
  • Multi-datacenter, geodiverse monitoring - Our monitoring system coordinates between datacenters in multiple geographic locations to minimize false alerts from partial network outages at your mail hosting facility.
  • Self-monitoring to minimize false alerts - Individual filtering hosts closely monitor their own status to ensure that local issues are promptly escalated and taken care of by our team. This prevents alerts for issues that are unrelated to your mail server or infrastructure.


Example email notifications

Mail host alert

Subject: Mail host alert:

Mail deliveries for are currently failing. Following is a sample error from our mail logs:
May 15 19:52:58 bolt104a postfix/smtp[29743]: 4QL0jS0fm8z8qvXk:, relay=none, delay=1009, delays=979/0/30/0, dsn=4.4.1, status=deferred (connect to[]:25: Connection timed out)

A follow-up email alert will be sent when the systems detect that deliveries have resumed.

Helpful links:
View queued mail:
View recent bounces:

This alert was sent from the SpamHero Mail Host Alert system. Use this link to disable these alerts or change where they are sent:

Mail host ok

Subject: Mail host ok:

Mail deliveries for have resumed working again. Following is a sample delivery from our mail logs:
May 15 20:35:04 bolt104a postfix/smtp[25685]: 4QL1tr0bTcz8qx2c:,[]:25, delay=344, delays=341/0.04/0.25/2, dsn=2.0.0, status=sent (250 ok 1684208104 qp 25879)
This alert was sent from the SpamHero Mail Host Alert system. Use this link to disable these alerts or change where they are sent:

Last updated August 7, 2023