Spam filter and Distribution Lists

Question

Hi all,

We have 2 distribution lists that are receiving a lot of spam. Does anyone know how to stop this. We used ORCA to scan our spam filter config and verything is okay. How does the spam fiter policy in office 365 covers distributiion lists?

Answer 1

@CroTeam
First, I want to say that no policy can block all spam, it can only minimize the amount of spam.

Does your distribution group receive needed ordering from specific external mailboxes? If so, you could add those mailboxes as mail contact. Then set your distribution group only receive email from those users:

If your distribution group doesn't receive email from specific external mailboxes. I want to confirm with you that whether the spam sent from specific mailbox/domain? If those spam from a specific mailbox/domain you could add it to the "Block lists" in Mail filtering.

If your distribution group need to receive email from random mailbox, those spam also sent from random mailbox, you may need to add those email address into Block lists one by one, in this way, it will cannot send spam to your organization again. You can also modify the setting of Anti-spam settings(such as block Empty messages, contains words in sensitive word list), to let it block more spam.

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Answer 2

There's nothing special when it comes to DGs, the anti-spam policies apply to them as well. If you are using those mostly for internal communication, simply change the address to something new, which should drastically reduce the amount of spam. Or use the delivery restriction feature.