As a user with the Advanced Search permission, you can search emails by their non-standard headers. These are the extra headers, starting with X-, that mail systems add to an email, such as X-Gm-Features or X-MS-Exchange-Organization-MessageDirectionality.

Search by a non-standard header

1. Go to the Search section, click the Email tab, and open Advanced Search.
2. In the field dropdown, select Non-Standard Headers.

3. Select a condition:
   • Contains Phrase (selected by default)
   • Does Not Contain Phrase
   • Contains All
   • Contains Any
   • Does Not Contain Any
   • Contains Keywords from Keyword List
   • Does Not Contain Keywords from Keyword List

4. In the Keyword field, type the header's value, the part after the colon. For example, for the header X-MS-Exchange-Organization-MessageDirectionality: Outgoing, type Outgoing.
5. Set the date Range and click Search.

Please note that:

• Type only the value. Searching for the header name, or for the name and value together (for example X-Gm-Features: Ac12FX…), returns no results.
• The search isn't case-sensitive, and the keyword needs at least 3 characters.
• Only non-standard (X-) headers are searched. To search by sender, recipients, subject or Message ID, use those fields instead.

Find an email's headers

To see which non-standard headers an email has, and their values:

1. Open the email from your search results.
2. Click More above the email and select View Raw Message.

The raw message opens in a new tab, with all its headers at the top.