I will be reffering to only the access tab in smtp virtual server
properties.

How does access control relate to relay restrictions, if at all?

If relay restriction is based purely on authentication, must authentication
be enabled in access control options for people to relay?

Would allowing anonymous access in access control options allow anyone to
relay?

I think it would be ideal if access control and relay restrictions had
nothing to do with each other, but I'm just not sure how the two interact.

The only way for an anonymous computer to relay is set the relay
restrictions to 'all except the list below' and empty the list, regardless
of access control or connection control?