sender callouts exchange 2010

Sender Callouts Exchange 2010

Challenge-Response is a spam-prevention system in which the first email contact from an unknown sender is bounced back with a "prove this is really you" message.
Once the sender jumps through whatever hoop the challenge-response system requires, they are allowed to send mail to the recipient.
The header shows the address of the message sender, the address of the message recipient, the message subject and other information.
Graylisting has spawned a couple of related techniques that also exploit the fact that spam mail senders don't follow the rules of smtp.
Greylist: Senders who are not block-listed (excluded) or allow listed (accepted) can be placed on a greylist.
Some anti-spam software can send greylisted addresses an automated response, challenging the sender to confirm their legitimacy.
When your computer is infected with a spam bot, the sender (you) unknowingly sends the spam.
Headers identify the sender and recipient of a message, the route the message took from one site to another and so on.
Blacklist all the senders that you don't know or email addresses from previous spam emails.
Set your email program like microsoft outlook express to not display the preview panel (see outlook express menu item 'view' then 'layout') because just opening a spam email might be enough to send information back to the sender that your email address is valid.
The use of buffers or third-party senders, helps to isolate the actual spammer from recrimination.