Preventing "real server connect failed" errors for MAPI

Occasionally, the following error may appear when a Virtual Service is using a wildcard:

Log error
kernel: L7: Real Server Connect failed (client:port->virtual service:wildcard port->real server:port)L7: Real Server Connect failed (client:port->virtual service:wildcard port->real server:port)

The LoadMaster forwards the traffic on a random port and the Real Server will reject it because the port is closed.

To fix this issue, add two static ports for the Offline Address Book (OAB) and Remote Procedure Call (RPC) on the Exchange 2010 Real Servers.

To do this, follow the steps below in the LoadMaster Web User Interface (WUI):

  1. In the main menu, select Virtual Services > View/Modify Services.
  2. Delete the Virtual Service that is using the wildcard port.
  3. Re-create the Virtual Service using port 135.
  4. In the Virtual Service modify screen, expand the Standard Options section.
  5. Enter the extra ports in the Extra Ports text box. Separate the ports by commas.

    tempsnip.png

 

When you click the View/Modify Services option in the main menu, you should see something similar to the screenshot below, for example; 192.168.10.15:135(+2)


Refer to the following Microsoft article for further details: Configure Static RPC Ports on an Exchange 2010 Client Access Server.

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ian.hardie

Is that a typo in the screenshot? The MS recommendation is to use anything over 59531, the screenshot shows 6000 - should it not read "60000, 60001" ?

MS Details from the KB you link to:

.PARAMETER RPCPort
Static port for RPC Client Access Service. If not specified, defaults to 59531. Microsoft recommends you set this to a unique value between 59531 and 60554 and use the same value on all CAS in any one AD site.

.PARAMETER ABPort
Static port for Exchange Address Book Service. If not specified, defaults to 59532. Microsoft recommends you set this to a unique value between 59531 and 60554 and use the same value on all CAS in any one AD site. Ensure this value is different from value of RPCPort.

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Justin Federico

@ian.hardie

Yes. This is a typo. Looks like one of the zeros was omitted from the screenshot in error. Thank you for bringing this to our attention.