Sender Policy Framework (SPF) & Email Clusters

OpenSRS's email service is provided through two clusters, Cluster A and Cluster B.  This articles provides information on each and instructs you on how to determine which email cluster you are on.

For Cluster A and B, please include _spf.hostedemail.com in the SPF record. The SPF record is a TXT entry that looks similar to the following:

v=spf1 include:_spf.hostedemail.com ~all

To allow outbound email notifications from OpenSRS to registrants sent on behalf of resellers, please include registrarmail.net in the SPF record:

include:registrarmail.net

Email Cluster A

All outbound email for both regular deliveries and filter-only deliveries originates from:

  • 216.40.44.0/24

All outbound forward and autoresponder traffic originates from:

  • 216.40.42.17 which has matching forward and reverse DNS of "forward.hostedemail.com"

All migration traffic originates from:

  • 216.40.42.15 (fetchmail-snat.a.hostedemail.com)

Email Cluster B

All outbound email for both regular deliveries and filter-only deliveries originates from:

  • 64.98.42.0/24

All outbound forward and autoresponder traffic originates from:

  • 64.98.36.17 which has matching forward and reverse DNS of "forward.b.hostedemail.com"

All migration traffic originates from:

  • 64.98.36.15 (fetchmail-snat.b.hostedemail.com)

Email Notifications to Registrants

Note: While the single IP addresses above can also have "/32" at the end (noting a single IP address in CIDR format), if there is no prefix-length provided with a listed IP address, /32 is assumed. As a TXT record can only be 255 characters in length, this method saves on unnecessary characters.

If you need help creating the SPF record, please try the SPF creation wizard.  After creating the SPF record, it can be check with this tool. Additionally, visit this site if you would like to know the ins and outs of SPF records.

Determine Your Email Cluster

The cluster is randomly assigned and can not be changed.  Both clusters have the exact same features and functionalities.  All email accounts created by the reseller will be under the same cluster.

To find out which cluster you are on:

1. Sign into the Reseller Control Panel

2. Click on the Email tab

3. Click on the Settings tab

4. The email cluster is displayed under Cluster Name


If you are setting up your first email service, see Step by step guide to setting up an email service for the quickest way to the service up and running.

Below are different settings depending on the cluster. Cluster B has an extra ".b" in the setting. Please replace yourdomain.com with the domain that you are setting up the email service for.  Please also note that the server name is spelled as hostedemail, not hostedmail.

Cluster A

MX Record: mx.yourdomain.com.cust.hostedemail.com

CNAME: mail.yourdomain.com.cust.hostedemail.com

Mail server:mail.hostedemail.com (or mail.emailhome.com)

Webmail sign in: https://mail.hostedemail.com (or https://mail.emailhome.com)

Cluster B

MX Record: mx.yourdomain.com.cust.b.hostedemail.com

CNAME: mail.yourdomain.com.cust.b.hostedemail.com

Mail server:mail.b.hostedemail.com (or mail.mailconfig.net)

Webmail sign in: https://mail.b.hostedemail.com (or https://mail.mailconfig.net)

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