In Exchange 2019 on-prem, I see DNS requests originating from my Exchange servers with transport roles. I'd like to force all DNS requests for outbound mail to take place only on my smart host. I have the "Use the external DNS lookup settings on servers with transport roles" option enabled on my send connector. Is there a way to ensure that my Exchange servers don't perform DNS requests for outbound mail?
In Exchange 2019 on-prem, how do I configure send connectors to disable DNS lookups?
22 Views Asked by Michael Dunkin At
1
You may set up smart host configuration:
In this configuration, DNSRoutingEnabled parameter of New-SendConnector cmdlet must be set as $false.
The cmdlet for smart host configuration is as follows:
New-SendConnector -Name -AddressSpaces * -Custom -DnsRoutingEnabled $false -SmartHosts [,...] [-SourceTransportServer ,...]
If you you have an existing send connector, when you define a second connector like above, you may disable the former connector then when the situation is stable you may delete the former connector.
You should not see DNS client queries that originates from the new Exchange Server Send Connector.
Ref: https://learn.microsoft.com/en-us/exchange/mail-flow/connectors/outbound-smart-host-routing?view=exchserver-2019