[Exim] Bounced Messages

We have exim running as a mail hub that delivers to our Mercury
servers. This works fine apart for one thing:

When exim bounces a message it sets the return path to <>.
However, when the message is returned to a mercury server, the
mercury server generates a delivey failure due to an invalid or illegal
from address.

Can the <> be changed to a valid email address?

Thanks for your time.



Gordon Carn BSc
Postmaster
Plymouth College of Further Education
Kings Road
Devonport
Plymouth
Devon
PL1 5QG
England

Tel: +44 (0)1752 305355