Disabling Local Anti-spam Checks

Once your MX records have been changed to our service, there is no reason to have any other anti-spam solutions operating. In fact, having multiple concurrent anti-spam solutions can increase your problems. We recommend that all other anti-spam services be deactivated. This may imply modifying configurations in your server, firewall, or router. This all depends on your infrastructure.

Make sure that all your domains are added to our filtering service before making these modifications. It is best to wait for the expiration of the TTL on your MX records before making these changes.

You can find our complete list of IP addresses by looking at the Related Articles at the bottom of the page.

Office 365/Exchange Online Microsoft Exchange
G Suite (Google Apps) Shared Hosting

Disabling Office 365/Exchange Online Anti-spam

To disable Exchange Online Protection (EOP): 

Login to the Office 365 Admin center  
Click on mail flow, rules, the plus sign, and selecting Bypass spam filtering
Input the options below and click save.
For more information, you may refer to this Microsoft article.

Here is the Powershell command to create the bypass with the new Hornetsecurity IP addresses : 

New-TransportRule -Name "Bypass Spam Filter Hornetsecurity/Zerospam" -Comments "Disable M365 spam filter for Zerospam/Hornetsecurity IPs" -Priority 0 -SenderIpRanges "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "" -SetSCL -1

Disabling Microsoft Exchange Anti-spam

Make sure Content Filtering is not active. If you have any other local antispam software running, make sure that it is not scanning contents sent from all of our IPs (see Related Articles)

General Instructions

Microsoft has several articles discussing Content Filtering management. Here is a general-use article that explains how to deactivate Content Filtering for external emails: Content Filtering Procedures

Microsoft Exchange 2013

You can read about managing Content Filtering for Exchange 2013 by reading this article.

Microsoft Exchange 2010

You can read about managing Content Filtering for Exchange 2010 by reading this article.

Microsoft Exchange 2007

You can read about managing Content Filtering for Exchange 2007 by reading this article.

Disable G Suite Anti-spam

Sign in to your Google Admin console. and navigate to Advanced Settings for Gmail.
(Apps →  G Suite →  Gmail →  Advanced settings.)
If multiple entries are shown in the Organizations section, highlight your domain (top-level org).
Under the Spam, phishing, and malware header, find the Inbound gateway option and click Configure.
Give the inbound gateway rule a descriptive name like "Inbound Email Filtering" to easily identify it later.
Under Gateway IPs, enter all IP ranges we have listed on our Filtering IP page and make sure to check all 3 relay options:
  • Automatically detect external IP
  • Reject all mail not from gateway IPs
  • Require TLS for connections from the email gateways listed above
Under Message Tagging, check " Message is considered spam if the following header matches" and enter X-Spam-Flag: NULL as the Regexp value. Make sure to also check " Disable Gmail spam evaluation on mail from this gateway".
Save your Inbound Gateway settings.
Review your inbound gateway settings and click Save at the bottom of the Gmail settings page.

Disable Anti-spam for a Shared Hosting Provider

Disable any local anti-spam that you might have running (server, email hosting, desktops). Two simultaneous anti-spam solutions make it difficult to diagnose email issues. Furthermore, our filtering provides you with complete protection.

Refer to your specific product's documentation for instructions on how to disable anti-spam.