Does SMTP Blocks allow the use of Wildcards?
Question asked by TOAST.net - 5/20/2024 at 9:33 AM
We keep seeing spammers who are changing their sub domain slightly (Ex:
@marinjoesrestaurant.onmicrosoft.com and @marinlaborers.onmicrosoft.com) The biggest culprit is those exploiting the "onmicrosoft.com" domain.  We can and have been adding the custom filters to combat these, but would like to reject it at the SMTP level before the message enters our server. 

We found that using the SMTP Blocks under settings-->security works well, but don't see any info on wildcard use in the documentation for the setting. Has anyone done that before or know if it is possible to do at the SMTP level for SM? Or have found a more effective way to combat this?

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Douglas Foster Replied
Short answer - Yes.
You can set SMTP to block *.onmicrosoft.com
or even @marin*.onmicrosoft.com
We have over 170 set up. Some of the ones we have set up include : 


www.HawaiianHope.org - Providing technology services to non profit organizations, low income families, homeless shelters, clean and sober houses and prisoner reentry programs. Since 2015, We have refurbished over 11,000 Computers !

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