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Can somebody please help me with this issue. In our company we are having issues sending emails to @hotmail.com addresses. I have contacted Microsoft "Support" directly about this issue and they suggested getting our Domain hoster to publish a SPF record to get around this. I have gotten our domain hosters to do this, but it has been 4 days and the problem is still happening. Below is the error message we get when we send an email to @hotmail.com addresses; I have replaced our domain with 'EXAMPLE'.

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. sd1-ex1.EXAMPLE.NET #5.5.0 smtp;550 SC-001 Mail rejected by Windows Live Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation problems. If you are not an email/network admin please contact your E-mail/Internet Service Provider for help. Email/network admins, please visit http://postmaster.live.com for email delivery information and support>

Our environment is Windows 2003 server with Exchange 2003. Office 2007. Thank you.

  • Just an update: I have found out that someone is using our domain to spam, which has put us on a blacklist. The site that has us blacklisted says that there is a problem with too much 'backscatter'. Please help!
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3 Answers 3

up vote 3 down vote accepted

We've had similar happen, and it is hard to figure out. What happened to us is that one of our mailers got put on one of the various Realtime Blackhole Lists (RBL's) out there, which MS Live was using in their spam/not-spam decision making. We had to get delisted from the RBL before we could deliver. Microsoft was singularly NOT helpful in this, as they're loath to tell people how to circumvent their spam checking.

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How did you find out which blacklist you were on? –  The Woo Aug 24 '09 at 0:25
    
Google for "rbl lookup". There are a number of services out there. We dropped in each of our potential sending mailers, and one was on there. We then worked with the RBL maintainer to figure out what the heck was going on. –  sysadmin1138 Aug 24 '09 at 1:14
    
Just a finishing note on this one. I got our domain hoster to put a SPF record against our domain name. This, plus some exchange tips from below has solved our spam issues. –  The Woo Aug 31 '09 at 1:47

You need to enable Recipient Filtering on your Exchange server. That will prevent the backscatter spam, although you'll still need to wait a few weeks to clear the blacklist (http://www.backscatterer.org/ has the details). To enable Recipient Filtering:

  1. Open Exchange System Manager
  2. Open Message Delivery properties (right click on Message Delivery under Global settings)
  3. Open the Recipient Filtering tab and check the "Filter recipients who are not in the Directory" option
  4. Open your SMTP virtual server properties. Click on the Advanced button.
  5. In the Advanced window, click on Edit
  6. Check the Recipient Filter checkbox and click Ok.
  7. Restart your SMTP virtual server
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Thank you for that. In point 3, do I have to add people in the domain into the list? –  The Woo Aug 24 '09 at 3:57
    
Nope. The filter recipients checkbox takes care of that for you –  zippy Aug 24 '09 at 6:37
    
You might have to enable the anti-spam feature upfront. See Technet on: Enable Anti-Spam Functionality on a Hub Transport Server –  Roman Sep 5 '12 at 12:31

This may be way off or it may be something that wasn't checked yet, but I went to a client once that was on multiple blacklists (the primary complaint was inability to email users on hotmail, and gmail) and it turned out they had the Exchange server communicating on the same static IP as the users internet traffic. I guess when the blacklisters checked out the IP and saw lots of traffic they assumed the IP was broadcasting SPAM. We registered a new IP block with the ISP and configured the Exchange to DNS seperately from the general Internet traffic. Of course we had to follow up with each blacklister to ask them to reevaluate the domain. All was running smoothly again within a few days.

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