[Exim] relay/addresses

Hi all,

In affort to combat open relaying and email abuse i've been looking into the
config of exim.

exim is already doing a good job with checking following.

rcpt to: <spamtest@???>
550 relaying to <spamtest@???> prohibited by administrator

rcpt to: <"spamtest@???">
501 <"spamtest@???">: recipient address must contain a domain

rcpt to: <spamtest@???@mydomain.com>
501 <spamtest@???@mydomain.com>: malformed address: @mydomain.com>
may not follow <spamtest@???

rcpt to: <spammer.com!spamtest>
501 <spammer.com!spamtest>: recipient address must contain a domain

rcpt to: <spamtest@???@[111.111.111.111]>
501 <spamtest@???@[111.111.111.111]>: malformed address:
@[111.111.111.111]> may not follow <spamtest@???>

however, exim still takes the following calls ......despite the fact that it
never sends them anyways.

rcpt to: <"spamtest@???>
250 <"spamtest@???> is syntactically correct

rcpt to: <spamtest%spammer.com@???>
250 <spamtest%spammer.com@???> is syntactically correct

rcpt to: <spammer.com!spamtest@???>
250 <spammer.com!spamtest@???> is syntactically correct

rcpt to: <"spamtest@???>
250 <"spamtest@???> is syntactically correct

rcpt to: <spamtest%spammer.com@???>
250 <spamtest%spammer.com@???> is syntactically correct

rcpt to: <spammer.com!spamtest@???>
250 <spammer.com!spamtest@???> is syntactically correct

(i am safe to assume that our mail server is pretty secure with regard to
open relaying.)

however, can someone suggest the sort of filters i may implement to the
config to deny it to begin with ? and if such filters are common place, to
where i may find it ? (a have already looked :)...)....or even a ppoint in
the right direction is appreciated.

best regards

chris g