We've done our best to make these urls safe and friendly, but some of your email recipients may be hesitant to click on a URL in you message that is not from your domain. You can supply a parameter called "CustomTrackingDomain" and provide the string to use as the first part of the URL used in click, open, unsubscribe, and microsite links that might be present in your email message. When we generate the link, we will use the string you supplied to build the url.
To make this work you’ll need to have a network administrator at your company make a change to your Domain Name Server (DNS). Once you’ve decided on the domain name to use, you’ll need to create a CNAME record in your DNS service.