When I installed virtualmin I had initially named the server vps.site-a.com, however now I'm using a different website on the same installation (site-b.com).
Some of the people I've been emailing will have my emails placed in their Junk folders. Upon some investigation I noticed that the path the email takes is through vps.site-a.com and not through smtp.site-b.com
How can I setup virtualmin so that emails that are generated from site-b.com show as being sent from the site-b.com server?
Once that's done I can look at reverse dns entries and ptr records, but for now this is the logical first step.