Prohibited custom email headers to use
We allow you to add custom headers to your transactional emails, although there are some that are reserved by either Dynosend or email providers/clients that you may not use and they will not go through our systems.
Here are some headers that you may not use:
Message data:
- Message-ID
- Date
- From
- Subject
- To
- Reply-To
- CC
MIME
- Mime-Version
- Content-ID
- Content-Base
- Content-Alias
- Content-Identifier
- Content-Length
- Lines
- Content-Type
- Content-Disposition
- Content-Transfer-Encoding
- Encoding
Client-specific
- Mail-System-Version
- Originating-Client
- Mailer
- X-Mailer
- X-Report-Abuse-To
Return Path Information
- Received
- Return-Path
- Authentication-Results
- Received-SPF
- Auto-Submitted
- VBR-Info
You may also not use provider-specific tags like X-Dynosend-Contact-Id (Dynosend), X-Mailgun-Dkim (Mailgun), X-SMTPAPI (Sendgrid) and any other tag that you have no right to use.
Using them will not have any impact on your email delivery or account and we will simply not include any unwanted custom headers when processing your email and it will be sent as scheduled.