A bounce is a system message that is returned with information about why an e-mail could not be delivered.

Bounces matching the following rules result in the bouncing e-mail address being deleted from our system.

• Rule #5 - Any one of a number of servers returns a string containing "mailbox unavailable" (see http://www.pobox.com/bounce-common.mhtml)
• Rule #8 - Any one of a number of servers returns a string containing "no such user"
• Rule #13 - A Yahoo.com server returns a string containing "This user doesn't have a sbcglobal.net account"
• Rule #41 - Any one of a number of servers returns a string containing "no mailbox here by that name"
• Rule #42 - A Yahoo.com server returns a string containing "Doesn't have a yahoo.*"
• Rule #45 - A Yahoo.com server returns a string containing "User unknown in virtual alias table"
• Rule #47 - Any one of a number of servers returns a string containing "user unknown" (see http://www.pobox.com/bounce-common.mhtml)  
• Rule #49 - A Yahoo.com server returns a string containing "This account has been disabled or discontinued"
• Rule #55 - An sbcglobal.net or pacbell.net server returns a string containing "Adressee Unknown"
• Rule #61 - Any one of a number of servers returns string containing "Invalid recipient" 
• Rule #74 - Any one of a number of servers returns a string containing "no mailbox here by that name"
• Rule #76 - A juno.com or netzero.com server returns a string containing "Account Inactive"
• Rule #77 - Any one of a number of servers returns string containing "Inactive User"
• Rule #78 - Any one of a number of servers returns a string containing "501 #5.1.1 bad address" 
• Rule #104 - Any one of a number of servers returns a string containing "Bad destination mailbox address" 
• Rule #119 - Any one of a number of servers returns a string containing "recipient no longer on server"  
• Rule #165 - A Yahoo.ca server returns a string containing "Doesn't have a yahoo.ca account."
• Rule #167 - Any one of a number of servers returns a string containing "unknown .* user" "
• Rule #168 - A Yahoo.co.uk server returns a string containing "This user doesn't have a yahoo.co.uk account"
• Rule #169 - A wacad.edu server returns a string containing "Rule #168 - A Yahoo.co.uk server returns a string containing "Not a wacad user"
• Rule #191 - Any one of a number of servers returns a string containing "551 not our customer"
• Rule #193 - Any one of a number of servers returns a string containing "No account by that name here"
• Rule #195 - A btinternet.com server returns a string containing "This user doesn't have a btinternet.com account"
• Rule #198 - Any server returns a string containing "The specified user does not exist on our system"
• Rule #199 - Any server returns a string containing "no such mailbox"
• Rule #200 - Any server returns a string containing "no valid recipients"
• Rule #201 - Any server returns a string containing "that user does not exist here"
• Rule #202 - Any server returns a string containing "Recipient Rejected: Account Suspended"
• Rule #203 - Any server returns a string containing "Unknown address error 550-'5.1.1 unknown or illegal alias"
• Rule #204 - Any server returns a string containing "recipient account suspended"
• Rule #205 - Any server returns a string containing "550 account expired"
• Rule #208 - A rediffmail.com server returns a string containing "rediffmail.com .* your envelope sender is in my badmailfrom list"
• Rule #209 - Any server returns a string containing "mail to that recipient is not accepted on this system"
• Rule #210 - Any server returns a string containing "user does not exist"
• Rule #211 - Any server returns a string containing "550 Administrative prohibition - unable to validate recipient"
• Rule #212 - Any server returns a string containing "User .* not listed in Domino"
• Rule #213 - Any server returns a string containing "550 .* recipient rejected"