Rejected inbound Diameter connection

Logged when the first message of an incoming connection does not identify a configured peer that may use the listener. The attached error states the reason: the message is not a valid Capabilities-Exchange-Request, the Origin-Host is not a configured peer of the local node, the peer's adjacency does not accept the listener, the Origin-Realm differs from the configured realm, or the TLS client certificate does not identify the Origin-Host. diameter_result_code is present when Radiator Server answered with a failure CEA: 3010 for an unknown or unauthorized peer and 5012 for an invalid CER. The connection is then closed.

Compare the peer's Origin-Host, Origin-Realm, certificate, and source address with the peer configuration. Repeated rejections from unknown addresses can indicate scanning.