Enable white-label feature

The article describes how you can set-up your custom vendor portal domain once you have enabled (upgrade) to add the Whitelabel add-on.

Once you have the domain setup, you will also get access to the custom Login and Signup Links.

Name and Host Settings

Cname Settings - this is completed with your domain registrar (the site where you purchased your domain)
Visit your favorite domain registrar and create a new CNAME record with the host value of portal and the value portal.puppetvendors.com.