You must configure and provide a custom domain before the Engagement Tracking or Custom Bounce Domain features can be used.
This requirement may be established for a number of reasons. First, for Custom Bounce Domains, this allows for email messages to be white-labeled to your own domain. Secondly, 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 users. Since 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 use, such as email.example.com the following CNAME record would need to be configured for the domain example.com:
email.example.com CNAME tracking.socketlabs.com
This record tells DNS systems that when looking up email.example.com, to redirect and actually look at the records for tracking.socketlabs.com.
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 only 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 links.example.com and bounces.example.com by setting the configurations as:
links.example.com CNAME tracking.socketlabs.com
bounces.example.com CNAME tracking.socketlabs.com
Enabling Custom Bounce in SocketLabs CP
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 > Custom Bounce Domain. The domain, in its entirety, should be entered into the 'Custom Host Name' field. Pressing the Validate button tests the DNS settings to validate that the CNAME has been configured correctly. 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.