Expert Spam Filtering

Expert Spam Filtering is Overton.cloud’s frontline protection that blocks spam from suspicious IP ranges which typically don’t host legitimate mail servers — stopping a large volume of junk before it ever reaches your inbox.

On by default

Expert Spam Filtering is enabled by default for all domains on Overton.cloud, protecting you without any manual setup.

How It Works

The system requires SMTP authentication for mail originating from questionable networks — including residential ISP ranges and known botnets. Legitimate senders that authenticate properly are unaffected, while unauthenticated connections from suspicious sources are refused. This dramatically reduces spam and phishing while keeping genuine mail flowing.

Managing the Setting

  1. Log in to the management panel
    Sign in at email.adastra.ad.
  2. Open the Control Panel
    Sign in to the Control Panel at email.adastra.ad.
  3. Go to Spam Filters > Advanced
    Adjust the Expert Spam Filtering settings from the advanced spam filtering section.

Limitations

Can’t disable with certain forwarders

Expert Spam Filtering cannot be disabled while you have email forwarders pointing to major providers such as Gmail, Outlook, Yahoo, AOL or T-Online. This restriction protects Overton.cloud’s sender reputation, which all customers rely on.

Troubleshooting

If a legitimate sender hits an authentication error because their network is being filtered, the right fix is to request a whitelist rather than disabling the feature.

  1. Request a whitelist first
    Submit the affected IP or sender at esf.mxroute.com (https://esf.mxroute.com).
  2. Note there are no user logs
    There is no user-accessible log of blocked connections, so capture the exact error message the sender received when reporting an issue.
  3. Open a support ticket if it persists
    For ongoing problems, contact design@overton.cloud.

Think twice before disabling

Disabling Expert Spam Filtering will expose you to a barrage of spam and phishing emails. Use the whitelist process at esf.mxroute.com to handle false positives instead.

Support Resources

Related: Email Forwarders, Default Folders, and Managing Domains.

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