CNAME Configuration for White-labeling Bounce & Engagement Tracking

Before the Engagement Tracking or Custom Bounce Domain features can be used, a subdomain must be configured.

Only a single custom hostname is required to enable both of these features, but it's also standard to create separate records for each as well depending on your use case. 
The need for a custom hostname via a subdomain to implement the features is important for several reasons.
With regard to Custom Bounce Domains, the subdomain allows for email messages to be white-labeled to your own domain. In addition to reflecting your domain, it allows for SPF alignment.
For Engagement Tracking, this customized domain is important because each user's email sending reputation can be insulated from the email sending reputations of other usersSince spam scoring systems typically fingerprint messages based on the domain names included in the message, links for various tracking events are most effective when using a custom domain name.
Syntax of the DNS CNAME Record

To configure a custom domain for, such as, the following CNAME record would need to be configured in DNS: CNAME

This record tells DNS systems that when looking up, to redirect and actually look at the records for

These records need to be configured wherever your domain hosts its DNS. 


Please be aware that modifications to DNS settings can take up to 48 hours to propagate, though often this process takes minutes.

DO NOT create 3 CNAME records for the Custom Bounce Domain feature!

The following suggestion is for if you already have a CNAME record created in your DNS that uses email as the sub-domain.

You can establish multiple CNAME records to have unique values in your URLs when compared to your bounce address. For example, you could create both and by setting the configurations as: CNAME CNAME

Enabling Custom Bounce in SocketLabs

Once the proper CNAME(s) have been configured in the organizational domain's DNS settings, the features can be configured from the SocketLabs Control Panel by clicking on Configuration > Advanced Authentication. If validation is successful, the settings page will allow the Engagement Tracking or Custom Bounce Domain feature to be enabled. If the domain's CNAME cannot be validated, this feature cannot be enabled.