Hey Daryl, et al,

I've just discovered something rather interesting after I enabled the
msa_networks feature in local.cf. What's happening is this:

1/ spam arrives at the sendmail box from someone who has used a
non-existent email address in our domain

2/ spamassassin clearly marks this as spam, sendmail adds the necessary
headers, modifies the subject and relays to exchange

3/ if exchange is configured to send a copy of received email to an
external account OR the message is destined for a non-existent mailbox,
exchange will initiate a connection with sendmail either for forwarding
mail or for NDR

4/ since the exchange box is now trusted via msa_networks, the email
receives a clean bill of health from spamassassin and sendmail proceeds
to remove the headers previously added for the incoming message except
for the subject line which is left with the previously changed header!

How can I tell sendmail milter not to remove any of the headers as the
email message is really still spam???

Although we could drop all spam and forget about this whole issue,
company policy dictates that any email destined to an existing recipient
mailbox will be delivered be it spam or not (false positives in the past
have left many weary of lost email)!