[exim] Freezing non relay_to_domains

Hi. I didn't see anything in the archives about this.

We have exim setup as a smart host which relays incoming mail for 3
of our domains to an internal mail server. "domainlist relay_to_domains
= " is set to these domains and "hostlist relay_from_hosts = " is set
to our internal IP addresses so we can send mail out. In the router
section we have the appropriate routers set up for these 3 domains to
forward mail to our internal mail server.

When I look in /var/spool/exim4/msglog/, I see a grip of frozen
messages to addresses having nothing to do with us. Here's an example
of one (with the domain and IP address changed):

2005-02-20 19:25:41 Received from <> R=1D34CW-0008Lg-Ce U=mail P=local
S=4399
2005-02-20 19:25:41 sciyzzoecqig@??? R=dnslookup
T=remote_smtp defer (-5 3): retry time not reached for any host

2005-02-21 10:14:14 mail.notourdomain.com [123.123.123.123]: Connection
timed out
2005-02-21 10:14:14 sciyzzoecqig@??? R=dnslookup
T=remote_smtp defer (11 0): Connection timed out

We are not an open relay but it looks like people are trying to send
mail through us....or something, and exim is keeping the mail until the
timeout is reached (timeout_frozen_after = 3d). I have no idea. Is there
a way I can stop this or have exim discard/reject these messages right
away?

Thanks!

-Matt