Definition
Sender ID combined SPF with a PRA (Purported Responsible Address) check. It never achieved wide adoption and is rarely used today.
Best Practices
- Focus on SPF, DKIM and DMARC rather than Sender ID.
- Keep PRA-related records if older systems expect them.
- Treat Sender ID as legacy for compatibility only.
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Related Glossary Terms
Apple App Password (Email)
An Apple app password is a generated, app-specific password used to sign into an email account through clients that do not support two-factor authentication.
Email Authentication Protocols
Email authentication protocols are technical standards that verify the identity of an email sender, helping mailbox providers distinguish legitimate mail from spam and phishing.
BIMI
BIMI (Brand Indicators for Message Identification) is an email standard that allows brands to display their logo next to their emails in supported email clients. It requires DMARC enforcement at quarantine or reject policy.
DKIM (DomainKeys Identified Mail)
DKIM (DomainKeys Identified Mail) is an email authentication method that uses digital signatures to verify that an email was not tampered with during transit and comes from a authorised domain.
DMARC (Domain-based Message Authentication)
DMARC (Domain-based Message Authentication, Reporting and Conformance) is an email authentication protocol that builds on SPF and DKIM to prevent domain spoofing and provide reporting on authentication failures.
Email Account Takeover
Email account takeover is when an attacker gains unauthorised access to a sender or subscriber email account, often to steal data or send spam.
Frequently Asked Questions
A legacy email authentication standard from Microsoft.
Rarely; SPF, DKIM and DMARC dominate.
Only for niche legacy compatibility.