We have a O365 hybrid environment with an on-prem exchange server that also serves as a SMTP relay. Is there a way to see who is sending messages to the relay server via IP address instead of the preferred method of using the DNS name?
We have a O365 hybrid environment with an on-prem exchange server that also serves as a SMTP relay. Is there a way to see who is sending messages to the relay server via IP address instead of the preferred method of using the DNS name?
No, the Exchange Server protocol logs will only show the IP address of the sending client. The DNS lookups are handled by the client itself, Exchange doesnt have any ability to know if the client is using DNS or sending to the IP directly.
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