Require that all senders are authenticated no longer working

Question

Hello,
I've already mentioned it in another thread, but maybe it's an update-issue in stead of server issue.
My problem: It seems (well, it doesn't work anymore, so it's an issue) that the option "Require that all senders are authenticated" on 'Distribution Group' not longer works. I really don't know why this happends and when it doesn't work anymore,
because it did work when creating the group (and the updates weren't available).
The situation (so maybe there's another option to find out what causes the problem):
Pineapp -> Exchange 2007 SP2 Rollup 4. The pineapp is being used before I installed updates of Exchange (and it did work with this setup), so in my opinion, this can't be the problem.
If someone could help me, or point me to a (new) direction so I can solve the problem with our Exchange server, that would be great :).

Answer 1

Update: When sending an email to the used distribution group, I get an bounce with 'authentication required'. When sending
an email to the user in the same group, the email is delivered in stead of bounced.
This is normal. You only enabled the  "Require that all senders are authenticated" on 'Distribution Group', but the users in the same group do not have 
"Require that all senders are authenticated" enabled.  So the users outside of your domain still can send the mail to the users without authentication.
To batch enable the "Require that all senders are authenticated" for the users, you can use the following method:
1. Create a organizational Unit (OU), move the users to this OU.
2. Open EMS, type:
Get-mailbox -OrganizationalUnit   |set-mailbox -requireSenderAuthenticationEnable:$true
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