We have recently found a new issue with Microsoft owned domains being rejected when relaying your outbound mail through Postini.

It’s a two fold issue. Postini is combating current clients acting as an open relay, which causes Microsoft to blacklist Postini IP address.

The second problem is Microsoft; they don’t have a way to white list the Postini IP address or any other IP in there filters. Each time they block Postini, a Google rep calls a Microsoft account rep, and it takes days for Microsoft to find all the Postini IP address and un-list them. While they are delisting the current address, more addresses get blocked, and we are stuck in a vicious circle.

The best fix, which isn’t a real fix, is allowing mail for MSN, Live, Hotmail and Microsoft to go out through your local DNS/SMTP before hitting the outbound Postini service. Everything else will still go outbound through Postini. To recap, this isn’t a real fix but it’s the best that we can do to stop the sending issues experienced when sending to these domains.

Set Up MAN/Hotmail Connector – Exchange 2003

1. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manger.
2. If administrative groups are enabled, expand the administrative group that you want to work with.
3. If it is available, expand Routing Groups, and then expand Connectors.
4. Right-click Connectors, point to New, and then click SMTP Connectors.
5. In the Properties dialog box, click the General tab.
6. In the Name box, type a descriptive name for the connector.
7. Next select: Use DNS MX records for routing, click Use DNS to route to each address space on this connector.
8. Specify at least one bridgehead server: Click Add.
9. In the Add Bridgehead dialog box, click the server that you want to use, and then click OK.
10. Click Add.
11. Click the Address Space tab, and then click one of the following: Set the connector scope as Entire Organization.
12. Click Add.
13. In the Add Address Space dialog box, click the SMTP address type, and then click OK.
14. Enter the e-mail domain/s and the cost. Here you will add [msn.com, hotmail.com, Microsoft.com and live.com]. Connector costs range from 1 to 100, with the lowest cost having the highest priority for routing. Make this the LOWEST PRIORITY!
15. Set the connector scope as Entire Organization.
16. Click Add.

Set Up MSN/Hotmail Send Connector 2007, SBS 08, Exchange 2010

After you have set up Reinjection and registered the IP of your outbound mail server in the Administration Console, create and configure a Send Connector on your Hub Connector Server.

1. Choose Organization Configuration -> Hub Transport.
2. Select Send Connectors.
3. Right click in the actions pane and choose New Send Connector.
4. Name the connector “Microsoft Outbound”.
5. Under “Select the intended use for this Send Connector” select Internet.
6. Click Add and enter the address space “hotmail.com, live.com, Microsoft.com and msn.com” so that these domains will be routed through the new connector.
7. Under Network settings, select “Route mail through the following smart hosts.”
8. Click Add.
9. Set the radio button to DNS, and finish out the connector.