Definition of "similar"

[wxPhil]

In general settings, under "Loop protection" Help informs us that:

"Max Similar Mails Per Day - When the number of similar mails exceed this value, additional mails will be automatically failed." The default is 100

What is "similar"? If I send out identical emails (say a company newsletter) to 101 users on my mailing list, will the last person net get theirs? Or does a different recipient mean the email is not "similar"? If not, hiding this setting is "Loop protection" seems a bit obscure, and will foil many mailing lists...

On a related topic, the next setting says:

"Max Mails Per Sender / Recipient Pair Per Day - When the number of mails sent from a single sender to a single recipient exceeds this value, additional mails will be automatically failed." Default is 300.

Who wants to send 300 emails to the same person each day? Why such a high default?

thanks...
Phil

[Code Crafters]

Similar mails is based on the Sender / Recipient Pair and the Subject if I remember correctly. The value is set high becuase this is an infinite loop protection system. This means that if the same mail bounces back and forth to the mail server on an infinite mail loop due to bad antivirus, DNS setup etc. then the mail will be stopped to prevent it looping inifinitely. Note that this system is not for stopping duplicate mails arriving in the mail server.

[mcknet]

I have a small problem with this option. It's stopping the delivery of e-mail from a security camera to a user. On rare occasions, a bird may get in front of the camera and cause the camera to take picture after picture and e-mail it to the user. After awhile, the e-mail is blocked. It's more of a problem to have this e-mail blocked than it is to have to delete 500 close-ups of a bird. The subjects are all different:

Eye 7 reports movement:20080403084854214
Eye 7 reports movement:20080403084848964
etc.

Is my only option to increase the max similar mails per day? I don't want to disable this protection completely.

Scott

[Code Crafters]

The Sender / Recipient pair is the definitely compared but it is possible that the subject isn't compared. You have an unusual situation where you may receive many similar emails which would normally be the pattern of SPAM mails but in your case may be geniune. You can simply raise the trigger threshold to a much higher number. After all an infinite loop will bounce infinitely although obviously the more bounces the greater traffic on your mail server but in your case I think a higher threshold would be fine and still better than losing this facility altogether. We once had a customer change from another mail server to Ability Mail Server which blocked an infinite mail that had been bouncing round their old mail server for nearly a year which is why this feature is useful.