How to test if a user part of a distribution list receives the email without sending any mail, to avoid spamming

Question

There is a distribution list with hundreds of users. A user complained not receiving any mails sent to this distribution list. After making changes in the OU, how do we ensure that the user receives a mail without actually sending a 'test' mail by spamming all the other hundred users who are part of the DL?

Answer 1

You can't reliably do this.

Spam filters may be picking up on the email based on the number of recipients receiving the same email as a factor - short of sending email to all the recipients, you can't activate this code in other peoples mail server.

Answer 2

Some general attempts you can do by yourself:

• Before starting, check carefully in your spam filters/folders if the mail is came back to you, and search for the reasons. Some email filters bounce back the spam or the black/grey listed site mail writing the reason, with a distribution list your email server can think about a spam attack too.

• [if possible] contact the email manager of the complaining user, asking them if the mail results processed/arrived. Because you received no error message it should be is in some of their filters (and kindly remember them that one of their user is complaining about it). [You can use this point after you tried some of the below steps].

Then a tedious problem solving approach:

1. Send a mail (plane text) to the complaining user from the distribution list email account.

   • If it will arrive you can see if it is the mail format or the sending modalities (jump to -> 5).
   • If it will not arrive your address is in some spam or blacklist filter (-> 2).

2. Send a mail to that user from a different email account, but from the same server used for the distribution list.

   • If it arrives your server is not blacklisted and your sending email server is not in a spam filter of the user; your original email address can be in spam filter (for the complaining user) or the sending modality can trigger some filter. (->FOUND, if you want continue from ->5 using this sending account to understand why...).
   • If it doesn't your server may be blacklisted or in a user spam filter (->3).

3. [If you can] Send a plain text mail to another user with the same mail provider of the complaining user, from the distribution list email account.

   • It it arrives your distribution list email account/server is not blacklisted on the receiving one, the problem should be in the complain user side (spam filters). (->FOUND)
   • If it doesn't your server should be blacklisted: (->4).

4. When the receiver mail provider rules are public you may search if your sending IP (or IP group) is in a black or gray-list. If they are not public contact their administrator and ask to handle the situation (kindly remembering that one of their user is complaining...).

5. Send the last email sent via the distribution list and not arrived, directly to (field to:) and only to that user from the distribution list email account.

   • If it will arrive is something in the sending modalities (->6)
   • If it will not arrive is something in the format (links, attachment...) that triggers some filter. (->*FOUND*), and it is probably in the complain user spam filter... if you can send to another user of the same complain-user server and he receive you can exclude receiving-server problems...

6. Send the last email sent from the distribution list, directly only to that user from the distribution list email account, with the same sending modalities used the first time (maybe you sent the list to yourself and in cc or bcc to the users).

   • If it will arrive you find the problem may be in the distribution mechanism (->7).
   • If it will not arrive is something in the sending modalities that triggers some filter. (->*FOUND*)

7. Make a distribution list only with the complaining user. Send the last email sent and not arrived to the new distribution list, from the distribution list account, with the same sending modalities used for the mail distribution list.

   • If it will arrive is something inside the original distribution list (-> 8)
   • If it will not arrive is something in the distribution list modalities that triggers some filter. (->FOUND)

8. Count the users belonging to the same email provider of the complaining user. Check if that number exceed the limit for spam filter (when the rules are available on the receiving email provider). There are spam triggers based on the content, other on the same content for different users, other on the number of receiving mail server users contacted in a short time from the same address, regardless the content of the mail...

Good Luck ;-)