Why are Received headers read from bottom to top?

Every mail transfer agent (MTA) prepends its own Received: line to the top of the header block. Therefore, the bottom-most Received: header represents the earliest hop closest to the sender.

Can an attacker forge the From header?

Yes. In raw SMTP, the DATA From: header is trivial to spoof unless the receiving server enforces DMARC alignment against valid SPF and DKIM cryptographic signatures.

Are my pasted email headers uploaded anywhere?

Never. All regex parsing and hop timestamp calculations execute strictly inside your browser's JavaScript engine.

What does dmarc=fail (p=quarantine) mean?

It means the message failed both SPF and DKIM domain alignment, and the domain owner's DMARC policy instructed your mail provider to quarantine the message into the Spam/Junk folder.

Cybersecurity

Email Header Analyzer: Trace Phishing Hops, SPF, DKIM & DMARC (2026)

Paste raw RFC 5322 email headers to decode SMTP relay hops, transit delays, Authentication-Results (SPF/DKIM/DMARC), and From vs Return-Path spoofing anomalies.Documentation & FAQs ↓

Phishing Email Header & SPF/DKIM/DMARC Analyzer — Interactive Console

Runs locally in your browser • Instant output

Paste Raw RFC 5322 Message Headers

Return-Path: <bounces@mailer- shady-promo88.ru>
Received: from mx.enterprise.example.com (mx.enterprise.example.com [10.20.0.15])
	by inbox.enterprise.example.com with ESMTP id 9912A
	Mon, 28 Sep 2026 06:42:19 +0000
Received: from mail-relay-untrusted.biz ([185.220.101.45])
	by mx.enterprise.example.com with ESMTPS id 7721F
	Mon, 28 Sep 2026 06:42:02 +0000
Authentication-Results: mx.enterprise.example.com;
	spf=softfail (sender IP is 185.220.101.45) smtp.mailfrom=shady-promo88.ru;
	dkim=fail (body hash did not verify) header.d=microsoft-security-alert.com;
	dmarc=fail action=quarantine header.from=microsoft-security-alert.com
From: "Microsoft 365 Security Team" <security-update@microsoft-security-alert.com>
Reply-To: "Urgent Helpdesk" <collect-credentials@protonmail.com>
Subject: URGENT: Your Corporate Vault Password Expires in 2 Hours
Message-ID: <9981234.fake@mail-relay-untrusted.biz>

Phishing Risk Score

100/100

High Spoofing Risk

SPF Verdict

softfail

RFC 7208 / 6376 / 7489

DKIM Signature

fail

RFC 7208 / 6376 / 7489

DMARC Alignment

fail

RFC 7208 / 6376 / 7489

Detected Header Spoofing Indicators

SPF authentication returned 'softfail'

DKIM cryptographic signature verification failed

DMARC alignment failed against organizational From header

Return-Path domain (mailer-) mismatches From domain (microsoft-security-alert.com)

Reply-To domain (protonmail.com) redirects replies away from From domain (microsoft-security-alert.com)

Envelope & Addressing Breakdown

From: "Microsoft 365 Security Team" <security-update@microsoft-security-alert.com>

Return-Path: <bounces@mailer- shady-promo88.ru>

Reply-To: "Urgent Helpdesk" <collect-credentials@protonmail.com>

Message-ID: <9981234.fake@mail-relay-untrusted.biz>

Reconstructed SMTP Received Hop Trace (Bottom-to-Top)

Hop #1: mail-relay-untrusted.biz → mx.enterprise.example.com

from mail-relay-untrusted.biz ([185.220.101.45]) by mx.enterprise.example.com with ESMTPS id 7721F Mon, 28 Sep 2026 06:42:02 +0000

Hop #2: mx.enterprise.example.com → inbox.enterprise.example.com

from mx.enterprise.example.com (mx.enterprise.example.com [10.20.0.15]) by inbox.enterprise.example.com with ESMTP id 9912A Mon, 28 Sep 2026 06:42:19 +0000

Ready

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[![Phishing Email Header & SPF/DKIM/DMARC Analyzer](https://img.shields.io/badge/ZerosUniverse-Free_Tool-ff6a00)](https://www.zerosuniverse.com/tools/email-header-analyzer/)

Blog / Documentation HTML Citation

<a href="https://www.zerosuniverse.com/tools/email-header-analyzer/">Phishing Email Header & SPF/DKIM/DMARC Analyzer — ZerosUniverse</a>

2026 Quick-Reference Cheat Sheet & Benchmark Table: Phishing Email Header & SPF/DKIM/DMARC Analyzer

Quick Answer & 2026 Technical Summary (email header analyzer)Updated 2026 Standard

Look for three red flags: (1) Authentication-Results showing spf=fail/softfail or dmarc=fail, (2) a Reply-To or Return-Path domain that differs from the visible From domain, and (3) an originating Received IP belonging to an unrelated hosting provider. Use this interactive email header analyzer above to test phishing header decoder, spf dkim dmarc header check, and trace email sender ip locally in your browser with zero server uploads.

Target Keyword Spec: email header analyzer  |  Modules: SPF, DKIM & DMARC Authentication Parser • Sender Alignment & Reply-To Mismatch Detector • Chronological SMTP Hop & Delay Tracer

Primary Focus: email header analyzer

Core Capability: phishing header decoder

Privacy Mode: 100% Client-Side (Zero Upload)

Technical Parameter / Module	Standard / Keyword Spec	Architecture & Validation Rule	Operational Use Case (2026)
SPF, DKIM & DMARC Authentication Parser	`phishing header decoder`	Extracts Authentication-Results and Received-SPF headers to show pass/fail/...	SOC Phishing Triage
Sender Alignment & Reply-To Mismatch Detector	`spf dkim dmarc header check`	Flags display-name spoofing where From:, Return-Path:, and Reply-To: domain...	Email Deliverability Debugging
Chronological SMTP Hop & Delay Tracer	`trace email sender ip`	Reconstructs the exact path across Received: relays with hop-by-hop latency...	SOC Phishing Triage
Execution & Privacy Architecture	`100% Client-Side WebCrypto / JS Sandbox`	0 Bytes Sent to External Servers	Safe for internal SOC & authorized lab artifacts
NIST SP 800-53 / OWASP Alignment	`OWASP ASVS v4.0.3 / NIST CSF 2.0`	Deterministic Rule & Header Verification	Maps findings to actionable hardening controls
Cryptographic & Entropy Standard	`SHA-256 / AES-256-GCM / Argon2id`	≥ 128-bit Effective Security Margin	Meets 2026 post-quantum & zero-trust baselines

Step-by-Step Workflow

4 Easy Steps

01Phase 1

Copy Raw Email Headers

In Gmail click 'Show original', or in Outlook/Apple Mail view 'Message Source', and copy the header block.

02Phase 2

Paste Headers or Load Sample Phishing Header

Paste the raw headers into the analyzer (or click Load Phishing Sample to test a simulated attack).

03Phase 3

Check Risk Score & Authentication Badges

Review the 0–100 Phishing Risk Score, SPF/DKIM/DMARC badges, and Return-Path/Reply-To domain alignment.

04Phase 4

Inspect SMTP Relay Timeline

Examine each Received hop from originating IP to final mailbox delivery.

Real-World Applications

SOC Phishing Triage

Inspect suspicious executive impersonation or invoice emails without uploading private headers to third-party servers.

Email Deliverability Debugging

Diagnose why legitimate transactional emails are landing in spam or failing DKIM alignment.

Related Editorial GuideWhat is Phishing? Spear-Phishing, Email Spoofing & Prevention Guide

Read Tutorial →

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Email Header Analyzer: Trace Phishing Hops, SPF, DKIM & DMARC (2026)

Reconstructed SMTP Received Hop Trace (Bottom-to-Top)

2026 Quick-Reference Cheat Sheet & Benchmark Table: Phishing Email Header & SPF/DKIM/DMARC Analyzer

Step-by-Step Workflow

Copy Raw Email Headers

Paste Headers or Load Sample Phishing Header

Check Risk Score & Authentication Badges

Inspect SMTP Relay Timeline

Real-World Applications

SOC Phishing Triage

Email Deliverability Debugging

Architectural Capabilities

SPF, DKIM & DMARC Authentication Parser

Sender Alignment & Reply-To Mismatch Detector

Chronological SMTP Hop & Delay Tracer

100% Local RAM Processing

What is Phishing? Spear-Phishing, Email Spoofing & Prevention Guide

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