RFC 822 defines the standard for Internet email headers. Any header that starts with X- is a custom header.
Use an online tool such as MXToolbox to copy-paste and analyze email headers.
| # | Mail Header Name |
|---|---|
| Accept-Language | |
| Authentication-Results | |
| Content-Language | |
| Content-Transfer-Encoding | |
| Content-Type | |
| Date | |
| From | |
| In-Reply-To | |
| MIME-Version | |
| Message-ID | |
| Received | |
| References | |
| Return-Path | |
| SpamDiagnosticOutput | |
| Subject | |
| Thread-Index | |
| Thread-Topic | |
| To | |
| X-Auto-Response-Suppress | |
| X-Exchange-Antispam-Report-CFA-Test | |
| X-Forefront-Antispam-Report | |
| X-MS-Exchange-Antispam-SRFA-Diagnostics | |
| X-MS-Exchange-AtpMessageProperties | |
| X-MS-Exchange-CrossTenant-FromEntityHeader | |
| X-MS-Exchange-CrossTenant-Id | |
| X-MS-Exchange-CrossTenant-Network-Message-Id | |
| X-MS-Exchange-CrossTenant-OriginalArrivalTime | |
| X-MS-Exchange-Organization-AuthAs | |
| X-MS-Exchange-Organization-AuthMechanism | |
| X-MS-Exchange-Organization-AuthSource | |
| X-MS-Exchange-Organization-ExpirationInterval | |
| X-MS-Exchange-Organization-ExpirationIntervalReason | |
| X-MS-Exchange-Organization-ExpirationStartTime | |
| X-MS-Exchange-Organization-ExpirationStartTimeReason | |
| X-MS-Exchange-Organization-MessageDirectionality | |
| X-MS-Exchange-Organization-Network-Message-Id | |
| X-MS-Exchange-Organization-SCL | |
| X-MS-Exchange-Processed-By-BccFoldering | |
| X-MS-Exchange-Transport-CrossTenantHeadersStamped | |
| X-MS-Exchange-Transport-EndToEndLatency | |
| X-MS-Has-Attach | |
| X-MS-Office365-Filtering-Correlation-Id | |
| X-MS-Office365-Filtering-HT | |
| X-MS-PublicTrafficType | |
| X-MS-TNEF-Correlator | |
| X-MS-TrafficTypeDiagnostic | |
| X-Microsoft-Antispam | |
| X-Microsoft-Antispam-Mailbox-Delivery | |
| X-Microsoft-Antispam-Message-Info | |
| X-Microsoft-Exchange-Diagnostics | |
| X-Originating-IP |