relay

Setting sender_host_reject_relay = * does most of what I need. The
only problem is that I am getting rejection of relays from local
machines also. Some of us are using Eudora on PC's, and relay via a
unix box (running exim). Now these relays are being rejected. I
believe it's because the client PC's machine names are not returned as
FQDN. For example:

1996-07-26 13:48:34 refused relay to DWu1@??? from
farhadspc [134.133.40.57]

Can we force the sender host to be qualified before testing?