Tools Diagnostics Beginner

Free UnderHost tools: DNS, SSL, email, security and SEO checkers

tools.underhost.com has free checkers for DNS propagation, SSL certificates, email deliverability (SPF, DKIM, DMARC), blacklists, security headers, PageSpeed, SEO and more. What each tool does and when to use it.

UnderHost NOC Network Operations

6 min read Updated October 2026

On this page

Overview
Domains and DNS
Email
SSL and security
Website and performance
SEO
Builders and helpers
Using results in a ticket

tools.underhost.com is a free set of checkers built by the UnderHost NOC. They are the same checks our support team runs first, so they are a quick way to find out why a site, an email or a certificate is not working, before or after you open a ticket. In CustomerPanel they are under Support → Tools.

Domains and DNS

Tool	Use it to
DNS Propagation Checker	See A, AAAA, MX, NS, TXT records, what public resolvers answer, CAA and DNSSEC. Check a nameserver change or a new IP
Domain Health Checker	One view of DNS, nameservers, registry (RDAP) status, expiry signals and mail readiness
Migration Readiness Checker	Preflight a site before moving hosts: DNS TTL, response, mail records, CMS and a cutover checklist

Email

Tool	Use it to
Email Deliverability Checker	Audit MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI and PTR hints. Start here when mail lands in spam
Email & Domain Diagnostics	Quick mail configuration audit with common misconfiguration warnings
Blacklist Checker	Check an IP or a domain's A record against common DNS blacklists used by mail filters

SSL and security

Tool	Use it to
SSL Certificate Checker	Check expiry, issuer, covered names, trust chain and HTTPS connectivity
Mixed Content Checker	Find insecure http:// assets that break the padlock after enabling SSL
Security Headers Checker	Grade HSTS, CSP, X-Frame-Options and other security headers
WordPress Security Scanner	Passive checks for XML-RPC, readme leaks, directory listing, REST exposure and HTTPS
VirusTotal URL & IP Scanner	Check a URL, domain, IP or file hash against VirusTotal reputation data
Port Exposure Checker	See which common hosting, mail, panel and database ports are open on a host

Website and performance

Tool	Use it to
Uptime & TTFB Checker	Check HTTP status and timing (DNS, connect, TLS, time to first byte). First stop when a site seems down
Redirect Chain Checker	Follow every redirect hop, find loops and long chains
PageSpeed & Core Web Vitals	Google PageSpeed scores for mobile and desktop with the top improvements
WordPress Help & Troubleshooting	Step-by-step fixes for white screens, 500 errors, database, email and caching issues

SEO

Tool	Use it to
Full SEO Audit	A score out of 100 covering title, meta, headings, canonical, robots.txt, sitemap, schema and images
SEO Meta Checker	Audit a page's title, description, H1, canonical, robots and Open Graph tags
SERP Preview	See how a page appears in Google and Bing results
Open Graph Preview	See the share card on Facebook, X and LinkedIn
Schema & JSON-LD Checker	Inspect structured data and rich result eligibility
SEO Helper	Meta tag generator, keyword density, robots.txt tester and sitemap validator
SEO Indexing Guide	Get a new site indexed by Google, Bing and Yandex

Builders and helpers

Tool	Use it to
Cron Expression Builder	Build a cron schedule visually, see the next run times and the cPanel command
Site Policy Generators	Generate security.txt, robots.txt and llms.txt files
Design Helper	Contrast checker, CSS gradients, box shadows and border radius
Website Migration Request	Ask the UnderHost team to move your website to us

Using results in a ticket

When you open a ticket about a site, email or certificate problem, paste the result (or the tool's page link) into the ticket. It saves a round of questions and gets you a faster answer.

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