Receive Connector RemoteIPRanges Limit

Exchange Server uses Receive Connectors for providing SMTP endpoints for incoming connections. A modern Exchange Server provides a default connector on TCP port 25. 

Sometimes you might require creating a new receive connector for selected incoming SMTP connections. A standard requirement is a receive connector for relaying messages to external recipients. This cannot (should not) be achieved using the default connector.

Each connector uses the RemoteIPRanges attribute to store the list of IP addresses of remote systems that can connect to that connector. The default connector utilizes the full IPv4 and IPv6 address ranges.

Your new receive connector requires at least a single IP address for a selected remote system that is supposed to connect to that receive connector. Using CIDR notation, you can add a single IP address, address ranges, or IP addresses.

RemoteIPRanges is a multi-value attribute with a limit of IP address entries that can be added. 

The maximum number of address entries you can add to that attribute varies. You can store approximately 1,300 entries.

When you exceed the number of values, you receive the following error message:

The administrative limit for this request was exceeded.    
+ CategoryInfo          : NotSpecified: (:) [Set-ReceiveConnector], AdminLimitExceededException    + FullyQualifiedErrorId : [Server=EX01,RequestId=ee9d45ad-418b-4172-9235-963eca1a7830,TimeStamp=18.08.2020    20:07:54] [FailureCategory=Cmdlet-AdminLimitExceededException] AC1E336E,Microsoft.Exchange.Management.SystemConfi  gurationTasks.SetReceiveConnector    
+ PSComputerName        : ex01.varunagroup.de

I have tested the number of values that can be stored in that multi-value attribute. Depending on the IP address format I was able to add 1,238 (172.80.x.y) or 1,244 (10.1.x.y) single IP addresses to the RemoteIPRanges attribute.

Plan your IP address configuration requirements carefully and avoid using single IP addresses. Preferably, you should use IP address ranges or IP address CIDR notation for networks.

Links

• Set-ReceiveConnector

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