[exim] Default user account

I just can't seem to find some documents on a default account or
redirect for my server. It seems to reject any non-local address, and
that also seems to eliminate any alias redirection (I tried
"*:mail-default").

It's something pretty simple, but I just can't find the right stuff...

Perhaps I need to add a router to handle all unknown addreses - can
someone point me in the right direction?

Cheers

Stephen