Email Authentication Results

RustMail parses email authentication headers and displays them in a dedicated Auth tab in the message detail view. No other local mail catcher offers this.

What It Shows

The Auth tab extracts and displays results from four header types:

Header	Standard	What It Tells You
Authentication-Results	RFC 7601	Aggregated DKIM, SPF, and DMARC verdicts from the receiving MTA
DKIM-Signature	RFC 6376	Signing domain (d=), selector (s=), and algorithm (a=)
Received-SPF	RFC 7208	SPF check result (pass, fail, softfail, neutral, etc.)
ARC-Authentication-Results	RFC 8617	Authenticated Received Chain results for forwarded messages

Each result is shown with a color-coded status badge:

Status	Color
pass	Green
fail / hardfail	Red
softfail	Amber
neutral / temperror / permerror	Orange
none	Gray
info (DKIM signature details)	Blue

Endpoint

GET /api/v1/messages/{id}/auth

Response

{
  "dkim": [
    { "status": "pass", "details": "dkim=pass header.d=example.com header.s=selector1" },
    { "status": "info", "details": "domain=example.com selector=selector1 algorithm=rsa-sha256" }
  ],
  "spf": [
    { "status": "pass", "details": "spf=pass smtp.mailfrom=alice@example.com" }
  ],
  "dmarc": [
    { "status": "pass", "details": "dmarc=pass header.from=example.com" }
  ],
  "arc": []
}

Errors

Status	Condition
404	Message not found

How It Works

RustMail does not perform cryptographic DKIM verification or DNS-based SPF/DMARC checks. It reads and parses the authentication headers that upstream mail servers have already added to the message. This makes it useful for:

• Verifying that your mail infrastructure adds correct authentication headers
• Debugging DKIM signing configuration (domain, selector, algorithm)
• Checking SPF alignment in staging environments
• Inspecting ARC chains on forwarded messages

If no authentication headers are present (common for locally-generated test emails), the Auth tab shows an empty state.