Thank you - at least I can stop looking.

I've managed to get my spam load down to managable proportions but there is one more check that could help.

I notice that on some of the spam that gets through both the From and the To addresses are the same (both are valid).

Can I filter out or reject all mail where the From and To addresses are exactly the same?

It can't be done with a global rule. With some programming you could do it using a policy or a daemon. Notice that From and To in the SMTP transaction (Mail from / Rcpt) isn't necessarily the same as in the mail headers.

/Rolf