Received Header
Definition
A header line prepended by each mail server that accepts a message in transit, recording the server's own identity, the IP or hostname it received the message from, and a timestamp. Reading from bottom to top reveals the relay path.
Related terms
- DKIM
- DomainKeys Identified Mail. A cryptographic signature placed in a DKIM-Signature header. The signing key sits on the sending server; the public key...
- DKIM (DomainKeys Identified Mail)
- A cryptographic signing mechanism: the sending server signs the message headers and body with a private key, and the receiving server verifies...
- DMARC
- Domain-based Message Authentication, Reporting and Conformance. A DNS policy that stacks on top of SPF and DKIM, telling receivers what to do...
- DMARC (Domain-Based Message Authentication, Reporting, and Conformance)
- A policy layer that requires the domain in the visible From header to align with a domain that passes SPF or DKIM....
- Envelope Sender (Return-Path)
- The address used at the SMTP protocol level for bounce notifications, recorded in the Return-Path header. It is distinct from the display...
- Message-ID
- A globally unique identifier assigned to each message by the originating mail server, recorded in the Message-ID header. It is set by...
- MTA
- Mail Transfer Agent. The server that relays mail server-to-server. Postfix, Exim, Sendmail and Microsoft Exchange are the common implementations. Speaks SMTP.
- MUA
- Mail User Agent. The client the user sees. Outlook, Thunderbird, Apple Mail, Gmail web, Spark, mobile apps. Speaks SMTP outbound and IMAP...
- SPF
- Sender Policy Framework. A DNS TXT record on the sender domain that lists the IP addresses authorised to send mail for that...
- SPF (Sender Policy Framework)
- A DNS-based mechanism by which a domain owner publishes the list of IP addresses authorised to send mail for that domain. A...
Explained in these topics
- Email Forensics: Protocols, Header Tracing, Spoofed MailAn audit line written by each MTA that handles a message, stamped onto the top of the header block. The chain reads bottom-up: the bottom Received is the origi...
- Email Header Analysis and Sender TracingA header line prepended by each mail server that accepts a message in transit, recording the server's own identity, the IP or hostname it received the message...