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Diagnostic Toolkit

Free Diagnostic Tools

Essential utilities for developers and system administrators. Debug email delivery issues, inspect domain security records, and map network ownership quickly.

Open SuperTool Run reputation check

One host. Every check.

Run SPF, DMARC, DKIM, email posture, MX, DNS, TLS, WHOIS, reverse DNS, and a blacklist sample for any domain or IP. Results stream in as each check completes, no signup required.

SPF DMARC DKIM BIMI MTA-STS TLS-RPT MX DNS TLS WHOIS rDNS Blacklist

Focused checks

Pick a single tool

Each tool is optimized for a specific record, host, or email artifact so you can debug one signal without opening a dashboard.

SPF Record Checker

Verify authorized senders, SPF syntax, and lookup risk before sender policy drift hurts deliverability.

DMARC Analyzer

Review DMARC policy, alignment mode, aggregate reporting destinations, and domain spoofing posture.

SSL Certificate Grade

Grade certificate trust, hostname match, expiry, CAA, and observed TLS metadata for public endpoints.

DNS Lookup

Resolve A, AAAA, MX, NS, CNAME, TXT, and related records when validating domain infrastructure.

DKIM Record Checker

Inspect DKIM selectors and public keys to confirm email signatures can validate correctly.

BIMI Record Checker

Check BIMI DNS records, logo references, and certificate signals used by supported inboxes.

MTA-STS Policy Checker

Validate MTA-STS DNS and policy files that protect inbound mail transport security.

TLS-RPT Record Checker

Review TLS reporting destinations that help catch mail transport failures and downgrade attempts.

MX Record Lookup

Inspect mail exchangers and priorities when diagnosing inbound routing or provider changes.

Reverse DNS Lookup

Check PTR records for sending IPs and infrastructure identity alignment.

ASN & IP Lookup

Map an IP address to network ownership, ASN details, and address context.

WHOIS Lookup

Review public registration, nameserver, and ownership signals available for a domain.

Email Header Analyzer

Paste raw headers to inspect authentication results, routing hops, delays, and delivery context.

SPF Record Generator

Build a valid SPF record from your senders and IPs, with a live DNS-lookup count and PERMERROR risk check.

DMARC Record Generator

Assemble a correctly ordered DMARC record with policy, alignment, reporting, and percentage tags ready to publish.

DKIM Record Generator

Build the _domainkey record name and TXT template for any selector and key type, with guidance on publishing your public key.

DNS Propagation Checker

Query Google, Cloudflare, Quad9, and OpenDNS in parallel to confirm whether a record has fully propagated or is still inconsistent.

SPF Flattener

Resolve an SPF record's full include chain and inline every ip4 and ip6 address into one record to cut DNS lookups below the PERMERROR limit.

Lookalike Domain Checker

Generate homoglyph, typosquat, and combosquat variants of your domain, then resolve each to flag which lookalikes are registered, accept mail, and pose a phishing risk.

Why use these tools?

Fast diagnostics before continuous monitoring

One-off checks are useful for triage. HostRepute turns the same operational signals into scheduled monitoring, alert routing, history, and team-ready reports.

Validate changes quickly

Run focused checks before and after DNS, certificate, or mail provider changes.

Share findings clearly

Readable output helps support, engineering, and deliverability teams discuss the same evidence.

Escalate into monitoring

Move from one-off checks into scheduled scans, alert routing, history, and noindex reports.

Need alerts instead of manual checks?

Monitor hosts continuously across blacklist, DNS, TLS, SNDS, and Google Postmaster signals with clear alerts and shareable reports.

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