What are the benefits when the send connector or receive connector is configured with the Exchange Servers group, or ExchangeLegacyServers group, or Partner group?
Routing Header
When a messaging server (e.g. Hub Transport Server) delivers a message, it stamps a header field into the message, such as The Received: header, which typically includes the name of the messaging server and a date-timestamp. The following resend fields may insert into the message Resent-Date:, Resent-From:, Resent-Sender:, Resent-To:, Resent-Cc:, Resent-Bcc:, and Resent-Message-ID:.
Routing headers that are inserted into messages can be used to misrepresent the routing path that a message traveled to reach a recipient.
X-Header
An X-header is a user-defined, unofficial header field that exists in the message header.
Messaging applications, such as anti-spam, antivirus, and messaging server applications may add their own X-headers to a message.
The X-header fields contain details about the actions that are performed on the message by the transport server, such as the spam confidence level (SCL), content filtering results, and rules processing status. Revealing this information to unauthorized sources could pose a potential security risk.
examples of X-Header
X-MS-Exchange-Forest-RulesExecuted--This X-header lists the transport rules that were performed on the message.
X-MS-Exchange-Organization-OriginalArrivalTime--This X-header identifies the time when the message first entered the Exchange organization.
Header firewall prevents the spoofing of these X-headers by removing them from inbound messages that enter the Exchange organization from untrusted sources. Header firewall prevents the disclosure of these X-headers by removing them from outbound messages that will go to untrusted destinations outside the Exchange organization. Header firewall also prevents the spoofing of standard routing headers that are used to track the routing history of a message.
So far, I do not see how to use the X-Headers and why we need them? First, check the receive connector at Edge Transport role server. Does it includes the ms-Exch-Accept-Headers-Routing?
