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Distribution List Not Getting Mails From Outside – NDR 5.1.1

When you create any distribution list with Exchange Management Console – EMC or Exchange management Shell – EMS in 2007 by default Sender Authentication is Enabled to prevent unwanted messages from spam.

Let’s say I have created a group “Group 11” in EMC and when I check the Sender Authentication setting through shell it shows enabled.


Get-DistributionGroup “Group 11” | Select-Object Name, RequireSenderAuthenticationEnabled



Now if you don’t disable it then group doesn’t get any mail from outside of organization and  sender gets NDR 5.1.1 which means Exchange doesn’t authenticate anonymous incoming connection for this group and reject it with this NDR.

So don’t forgot to disable the Sender Authentication after creating any groups in Exchange 2007.


Disable the Sender Authentication

Set-DistributionGroup “Group 11” -RequireSenderAuthenticationEnabled $False

Verify once it is disabled.

Get-DistributionGroup “Group 11” | Select-Object Name, RequireSenderAuthenticationEnabled


Hope this helps who are migrated from Exchange 2003 to 2007!!!!


Written by Amit Tank

May 18, 2008 at 11:45 am

6 Responses

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  1. […] Distribution List Not Getting Mails From Outside – NDR 5.1.1 […]

  2. I think you should only enable groups to get mail from outside your organization if you have too. Disabling sender authentication for no reason seems like it would open up your organization to spam and other security threats


    June 5, 2008 at 6:20 am

  3. […] We recently installed Exchange Server 2007 and noticed that any new distribution lists were not receiving email from any outside addresses. Turns out that this is turned off by default in Exchange Server 2007 and needs to be enabled.  The Exchange Server Share blog has an article describing how to fix this. […]

  4. This did not fix our problem. We ended up deleting the group we created on Exchange 2007 and recreating them on Exchange 2003. This was the only thing that fixed the problem. We were getting NDR 5.7.1

    Eric Chatham

    September 16, 2008 at 5:31 pm

  5. How do I do a dynamic distribution list that select the members of a group defined in my Active Directory?

    Carlos Villalba

    November 12, 2008 at 11:54 am

  6. How long does this take to update? I did this an hour or so ago and I’m still getting User Unknown. :(.

    Chase Hansen

    November 25, 2008 at 3:23 pm

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