For inbound customers including Email Gateway, Email Forwarding and Spam Filtering the headers we inject are:
| Header Key | Header Description and Example Value |
| X-HalonDuo-ID | Unique Message ID 20fsdf1859-210c-11ea-9b56-5b3414d4d306 |
| X-HalonDuo-CID | Customer ID of the account owning the inbound domain <numerical, natural number> |
| X-HalonDuo-SID | Service ID of inbound domain <numerical, natural number> |
| X-HalonDuo-Scores | JSON-encoded list of spam scores assigned to the message {"rpd":"unknown", "sa":0, "sa_scores":{"FREEMAIL_FROM":0.001, "HTML_MESSAGE":0.001}} |
| Envelope-Sender | Identifies the SMTP "MAIL FROM" provided by the sending server [email protected] |
| Received | We prepend a Received header with information identifying the server which processed the message, as required by RFC-5321. Received: from mail-yb1-f173.google.com (mail-yb1-f173.google.com [209.85.219.173]) by inbound4.eu.mailhop.org (Halon) with ESMTPS; Tue, 17 Dec 2019 |
| Received-SPF | Result of our SPF check. none | hardfail | softfail | pass |
| Authentication-Results | Extended SPF / DKIM / DMARC check results <our server hostname>; spf=softfail smtp.mailfrom=example.com; dkim=pass header.d=example.com header.s=selector header.a=rsa-sha256 header.b=<hash>; dmarc=none header.from=example.com; |
| ARC-Seal ARC-Message-Signature ARC-Authentication-Results | Authenticated Received Chain (ARC) headers, as described in RFC-8617. |
Outbound email have the headers:
X-Mail-Handler: DuoCircle Outbound SMTP
X-Originating-IP: xxx.xxx.xxx.xxx
X-Report-Abuse-To: [email protected] (see https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information for abuse reporting information)
X-MHO-User: xxxxxxx