Been having some email issues.
Turns out that my IP address is now blocked by spamhaus.org
Going through my Hosting service (Hosting Matters -- excellent service, cannot recommend them enough!) to figure out what is happening.
Fun, fun, fun...
And yes, I run several anti-virus apps and yes, I log outgoing packets -- checked the most recent logs (they recycle after seven days) and there is nothing on my system that is sending (or trying to send) out anything untoward.