This article lists common questions for Perimeter end users, as well as common service management, and refers you to articles that contain the answers. There is also a list of resources at Documentation, which might be of help.
Yes, to avoid delivery problems you need define properly your SFP record on yours DNS to include perimeter servers as allowed to relay mails from your domain name. Please find more info at this KB entry
If you need enable your incoming mail protection, you should also modify your Domain MX records to perimeter MX records so all your mail can be protected and delivered back clean. Please find more info at this KB entry