I seem to pop onto and pop off www.backscatterer.org
I found this, which seems to describe a technique to stay off. But in short, the domain I use for the server is different to the domains I accept mail for, so I’m not sure if the full set of changes is appropriate.
Has anyone thoughts on this, and making the changes using the GUI?
It’s nothing to do with the domains you accept mail for it who your mail server sends to. If any email accounts have forwards to external addresses including any web forms then how you configure your mail server will have no effect in this regard but of course it should still be configured correctly.
You can edit the conf files via the GUI if you wish.