Domain and security tools for SSL, blacklists and technical reputation
Free individual checks and generators · without registration
Check domain and DNS configuration, HTTPS, and security headers. For e-mail problems, separate checks are available for SPF, DKIM, DMARC and public block lists.
Secure domain, hosting and history
- Domain Name GeneratorGenerate domain names for free: from terms, industry and location. With endings, length filters, hyphens, umlauts, favorites and export. Without registration.
- WHOIS & Domain Age CheckerCheck domain age and WHOIS data for free: age from the registration date, registrar, status and nameserver. With source and clear boundaries in the case of missing data.
- Hosting provider checkerCheck hosting hints of a domain for free: separately classify IP addresses, network operators, ASN, name servers and recognizable CDN infrastructure.
- Domain History CheckerView domain history for free based on Internet archive recordings. With a time overview, direct archive links and a clear demarcation to the domain age.
- Determining the IP address of a domainDetermines the IPv4 and IPv6 addresses of a website, domain or URL. Ideal for DNS, hosting, CDN and infrastructure checks.
- Reverse DNS / PTR CheckerCheck Reverse DNS for free: Resolve IPv4 or IPv6 in PTR hostnames and compare them to the forward resolution. With clear error assignment.
- CMS CheckerWhich CMS uses a website? Recognize WordPress, TYPO3, Shopify and other systems based on public HTML signals. Free of charge with specific references.
Checking DNS and provider change
- DNS CheckerChecks A, AAAA, CNAME, MX, NS, TXT, SOA, CAA and recognized SPF and DMARC guidelines of a domain.
- DNS propagation checkerCompare DNS changes for free on Google Public DNS and Cloudflare. With records, TTLs, NXDOMAIN and transparent classification of deviations.
- DNS Moving CheckCompare DNS records for free before and after a move. Capture snapshots, import them locally and detect new, removed or unchanged records.
HTTPS and browser security rules
- HTTPS CheckerChecks HTTPS forwarding, certificate, and HSTS – to detect incorrect destination URLs or certificate issues after an HTTPS changeover.
- SSL CheckerChecks the certificate of your domain, issuer and expiration date – even if the domain redirects to another website.
- Security Header CheckChecks key security headers such as HSTS, CSP, X-Frame Options, Referrer Policy and other security headers of a URL.
- CSP Generator & Policy TesterCreate CSP for free and test resource URLs against a policy. With directives fallbacks, several policies, report-only and clear test limits.
- Mixed Content CheckerFind HTTP resources and insecure form targets in HTTPS pages and CSS.
- Google Fonts CheckerCheck Google Fonts for free: detect external style sheets, CSS imports, font files and connection instructions with references. Without registration.
- CORS CheckerCheck CORS for free: Compare Origin, Credentials, desired method and header with GET and OPTIONS responses. Without transmitting access data.
Email configuration and block lists
- SPF CheckerCheck SPF record for free: evaluate TXT entry, IP networks, include, redirect, recursion errors and DNS mechanisms. With comprehensible instructions.
- DKIM CheckerCheck DKIM for free: query domain and selector, evaluate public key, RSA key length, Ed25519 and revoked keys. Without test mail.
- DMARC Checker and GeneratorCheck and create DMARC record free of charge: Policy, subdomain inheritance, SPF/DKIM alignment and track reporting address. With DNS generator.
- Blacklist checkersChecks domain and IP against DNSBL/RHSBL lists and complements mail DNS. Helps to classify list hits and the reference to the actual shipping IP.
Then they join the exams.
Differentiate domain and service
First, determine which DNS records and IP addresses belong to the affected service. Website, incoming e-mail and outgoing shipping can use different providers.
DNS CheckerTargeting a change
When moving, compare old and new DNS stands. After changes to TLS or headers, on the other hand, you control the specific website response.
DNS Moving CheckInvestigate Mail Problems Separately
Check shipping permissions, signatures and the DMARC policy. For a blacklist check, the actual sending IP is relevant; an MX entry first describes the incoming mail path.
SPF Checker
Frequent questions
Does the hosting checker always show the actual web host?
Not mandatory. Publicly identifiable IP networks can belong to a CDN, proxy or intermediate provider. The results are technical notes, not contract information.
Does a blacklist hit mean a worse Google ranking?
No. DNSBL and RHSBL hits relate to the respective domain or IP and the purpose of the list. They are not proof of a Google devaluation or a safe browsing warning.
Checking the website in connection
The free SEO check examines up to 20 URLs and bundles findings and prioritized measures.