xdomain.com is black listed but some users get mail from xdomain.com

[evr72]

Hello,

I am having an issue where a customer's domain has been blacklisted.
The blacklisted domain send an email to the users in my domain. Some of the users get the email and others send an NDR saying x.xx.xxx.x(mydomain) does not like recipient.
Remote host said: 550 5.2.1 Mail from xxx.xx.xxx.xx(customers domain) refused: spam site.

I understand why is getting blocked, what I don't understand is howcome a couple of the users in my domain get the email, shouldn't it get blocked?

thanks!!

 

[58sniper]

Safe sender aggregation? Do those people have contacts for those email addresses that are sending? Is the domain in their safe sender list?

Pat Richard MVP
Plan for performance, and capacity takes care of itself. Plan for capacity, and suffer poor performance.

http://www.exchangeblogs.com/

 

[evr72]

I checked on that and no, user has not added to safe sender list