Because cPanel does not have the concept of aliases separate from forwarders, I've implemented quite a few forwarders for customers in place of the aliases they had on our previous server (although oddly, forwarders are called aliases in the exim config files, go figure).

So, let's say there's a mailbox a@b.com. A's brother Z does not have or want an account on b.com, but wants to advertise the address anyway. So I set up a forwarder:

z@b.com --> z@earthlink.net

Tonight I'm looking at the exim mail queue and what's this?

=> discarded R=has_alias_but_no_mailbox_discarded_to_prevent_loop

What the heck? Is this saying that if I want z@b.com to be a legit forwarder then I also have to create a mailbox for z on the domain? What is the logic of this? Doesn't it kind of defeat the purpose of a forwarder? And what loop would be created? I've administered other mail servers where forwarders work fine without accompanying mailboxes, and never had a loop problem.

Can anyone shed light on this?

Thanks,
Scot