BLACK LISTS, SMTP ERRORS, SPOOFING

We get many questions on WHY email gets bounced back to the sender. 

1. Monitor Blacklists: Regularly check the major spam databases and blacklists to ensure you or your email provider has not been added. Click here for a list of spam blacklists and here to check your DNS against MAPS and SPAMCOP, two of the more popular black list databases. (You will not receive a bounce message as a result of a blacklist, even though the email has not been delivered.)  SMTP error codes here.
    

Defining Soft and Hard Bounces

A soft bounce is an email message that gets as far as the recipient's mail server (it recognizes the address) but is bounced back undelivered before it gets to the intended recipient. A soft bounce might occur because the recipient's mailbox is full, the server is down or swamped with messages, the message is too large or the user has abandoned the mailbox. Most email service providers will attempt to deliver the email regularly for a few days. If it is still undelivered, it becomes a hard bounce.

A hard bounce is an email message that has been returned to the sender and is permanently undeliverable. Causes include invalid addresses (domain name doesn't exist, typos, changed address, etc.) or the email recipient's mail server has blocked your server. Servers will also interpret bounces differently, meaning a soft bounce on one server may be classified as a hard bounce on another.

And then there is the SPAM issues....

1. Understand and Monitor Spam Filters: Get to know the more common things that most spam filters, including Microsoft Outlook's Junk Filter. Click here to see a list of many of the major spam filters. Also, click here to view the terms reviewed by Spam Assassin one of the more popular spam filters. (Spam filters also will not generate bounce messages.)
   
    

BLACK LISTS, SMTP ERRORS, SPOOFING