prevent all ndrs in sendmail

Prevent All Ndrs In Sendmail

Munging: Disguising an email address to prevent it from being automatically collected and used as a target for spam.
Aspam blocker prevents you from receiving most spam so that you won't have to take the time to delete them.
Anti-spam software will spare you the trouble of clearing your inbox each morning, not only will you not have to manually delete junk mail, you can also block specific senders, thereby preventing the mails being resent to you in the future.
Sender verification callout: A spam-prevention system in which the identity of the sender of incoming email is verified before the email is accepted.
Domain Name System Block Lists (DNSBL) are commercial lists of networks that either allow spammers to use their systems to send spam, or have not taken action to prevent spammers from abusing their systems.
Right now, unfortunately, spf isn't in widespread-enough use to be viable as a spam-detection tool though it is beneficial in preventing bounces to innocent mail users whose addresses have been forged into the spam.
A Mousetrap makes use of javascript which prevents a reader from leaving a web site.
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.
Firewall: A piece of hardware or software (or a combination of both) designed to prevent unauthorized accessing of your computer.
To prevent abuse, each user is rated based on the material they flag.