ServerRecords

About ServerRecords

ServerRecords is a free DNS and email diagnostics toolbox. It lets you look up DNS records (including the DNSSEC family), check email authentication (SPF, DKIM, DMARC, BIMI, MTA-STS, TLSRPT), test mail servers over SMTP, inspect HTTPS connectivity and security headers, check blacklists, look up WHOIS registration and IP ownership, and generate SPF/DMARC records and strong passwords — all from one page, with plain explanations instead of raw technical output.

Beyond diagnostics, ServerRecords also carries the everyday utilities a system administrator reaches for: a subnet calculator that works out address ranges, masks and host counts for both IPv4 and IPv6; a RAID calculator for usable capacity, fault tolerance and hot-spare planning; a transfer-time calculator that turns bandwidth and file size into a realistic estimate; a MAC-address vendor lookup; a bulk GUID/UUID generator; and your own public IP, shown right at the top. These are single-purpose and instant — most run entirely in your browser, and none need an account.

Pick a lookup type from the picklist, enter a domain or IP address, and run the look up — or use Check Availability for an instant registered-or-available answer on a domain. By default, DNS look ups return every record type at once, and the Email Health and Domain Health checks roll several look ups into a single scored report. Results are organised into clear category tabs — opening with a domain-details card that shows registration, expiry and the detected DNS host — and every finding is tagged with a severity and can be expanded for its raw value and a help link.

Your last 20 look ups on this device are kept in the History panel (a sidebar on desktop, an expandable panel on mobile) so you can revisit a previous result without looking it up again.

Every look up is performed live, on demand — using public DNS resolvers, a DNS-over-HTTPS service for DNSSEC-family records, RDAP and blacklist services, and by connecting directly to the domain you enter over HTTP(S) or SMTP where a check requires it. Nothing is scheduled, monitored, or stored on our servers. See the Privacy Policy for details.

The SPF and DMARC generators go further with a built-in setup guide: enter your domain, create your record, and ServerRecords detects where your DNS is hosted and guides you through publishing it — step-by-step instructions for your provider, plus a link to their official guide, so you never have to hunt for where each setting lives.

Everything in ServerRecords

ServerRecords bundles a full set of DNS, email-authentication, security and networking tools — all free, with lookups running server-side or entirely in your browser. Here is everything included:

Overview

  • All DNS Records Look Up — Look up every DNS record type for a domain at once — A, AAAA, MX, TXT, CNAME, NS, SOA, CAA, SRV — plus SPF, DMARC and WHOIS, with plain explanations.
  • Email Health Check — One combined look up of everything that affects a domain's email deliverability: MX, SPF, DMARC, MTA-STS and TLSRPT.
  • Domain Health Check — One combined look up of a domain's overall state: all DNS records, WHOIS registration, HTTPS connectivity and security headers.

DNS Records

  • A Record Look Up — Look up a domain's A record — the IPv4 address it resolves to — with a plain explanation of what it means.
  • AAAA Record Look Up — Look up a domain's AAAA record — its IPv6 address — with a plain explanation of what it means.
  • MX Record Look Up — Look up a domain's MX records to see which mail servers handle its incoming email, in priority order.
  • TXT Record Look Up — Look up all of a domain's TXT records — used for SPF, domain verification, and more — in one place.
  • CNAME Record Look Up — Look up a domain's CNAME record to see which other hostname it's aliased to.
  • NS Record Look Up — Look up a domain's NS records to see which nameservers are authoritative for its DNS.
  • SOA Record Look Up — Look up a domain's SOA record — the administrative metadata for its DNS zone.
  • CAA Record Look Up — Look up a domain's CAA record to see which certificate authorities are allowed to issue SSL/TLS certificates for it.
  • SRV Record Look Up — Look up a domain's SRV records, used to locate specific network services like VoIP or chat.
  • PTR Record Look Up (Reverse DNS) — Perform a reverse DNS look up to find the hostname an IP address maps back to.
  • DNSKEY Record Look Up — Look up a domain's DNSKEY records — the public keys resolvers use to verify DNSSEC signatures.
  • DS Record Look Up — Look up a domain's DS record — the parent-zone anchor that links its DNSSEC keys into the chain of trust.
  • NSEC Record Look Up — Look up a domain's NSEC records — DNSSEC's mechanism for proving a name doesn't exist.
  • RRSIG Record Look Up — Look up a domain's RRSIG records — the actual DNSSEC signatures covering its record sets.
  • CERT Record Look Up — Look up a domain's CERT records — an uncommon record type for storing certificates in DNS.
  • IPSECKEY Record Look Up — Look up a domain's IPSECKEY records — keying material for opportunistic IPsec tunnels.
  • LOC Record Look Up — Look up a domain's LOC record — an informational record publishing geographic coordinates in DNS.
  • DNSSEC Status Look Up — Check whether a domain is DNSSEC-signed, anchored to the chain of trust, and actually validating.

Email Authentication

  • SPF Record Look Up — Look up a domain's SPF record and see, in plain language, which mail servers it authorizes to send email.
  • DKIM Record Look Up — Look up a domain's DKIM record for a given selector, and see whether it publishes a valid public signing key.
  • DMARC Record Look Up — Look up a domain's DMARC policy and see, in plain language, what it tells mail servers to do with mail that fails authentication.
  • BIMI Record Look Up — Look up a domain's BIMI record and see whether it publishes a brand logo for authenticated email.
  • MTA-STS Look Up — Look up a domain's MTA-STS record and policy file to see whether inbound mail is required to use encrypted, authenticated delivery.
  • TLSRPT Look Up — Look up a domain's TLSRPT record to see where SMTP TLS delivery failure reports are sent.
  • SMTP Server Test — Connect to a domain's primary mail server and check its greeting, EHLO response, and STARTTLS support.

Security

  • HSTS Look Up — Check whether a domain's website sends the HTTP Strict Transport Security header, and for how long.
  • HTTP/HTTPS Look Up — Check whether a domain's website responds over HTTPS and whether plain HTTP correctly redirects to it.
  • llms.txt Look Up — Check whether a domain publishes an llms.txt file summarizing its content for AI tools and crawlers.
  • Blacklist Look Up — Look up whether a domain's mail server IP address is listed on major email blacklists (DNSBLs).

Domain Info

  • WHOIS Look Up — Look up a domain's registration details — registrar, creation and expiry dates, and nameservers.
  • IP Ownership Look Up — Look up which network operator (ASN) and regional registry an IP address belongs to.

Tools

  • Password Generator — Generate a strong, random password in your browser — length, character sets, and ambiguous-character exclusion are all configurable.
  • SPF Record Generator — Build a valid SPF TXT record from a list of authorized mail sources, without memorizing the syntax.
  • DMARC Record Generator — Build a valid DMARC TXT record with your chosen policy, alignment mode, and reporting addresses.
  • SPF Flattening — Resolve a domain's SPF includes, a, and mx mechanisms down to raw IP addresses to help stay under the 10-lookup limit.
  • CT Subdomain Resolver — Discover a domain's subdomains from public Certificate Transparency logs and resolve each to its IP addresses — for building router allowlists when wildcard matching isn't supported.
  • Mail Header Analyzer — Paste the raw headers of an email you received and get each field analyzed — SPF/DKIM/DMARC results, the delivery path with per-hop delays, and sender consistency checks.
  • GUID / UUID Generator — Generate random version-4 UUIDs (GUIDs) in your browser — in bulk, with optional uppercase and hyphen-free formatting.
  • Subnet Calculator — Calculate subnet details for IPv4 (network, broadcast, usable host range, host count, subnet & wildcard masks) or IPv6 (network, address range, address count) from an address and CIDR prefix.
  • Transfer Time Calculator — Estimate how long a file takes to transfer at a given connection speed — enter the file size and bandwidth to get the time.
  • RAID Calculator — Calculate usable capacity, fault tolerance and storage efficiency for RAID 0, 1, 5, 6 and 10, including hot spares.
  • MAC Address Vendor Lookup — Identify the hardware manufacturer behind a MAC address from its OUI prefix, and see whether it is universally or locally administered.
  • DMARC Report Parser — Parse DMARC aggregate (RUA) reports — paste the XML or upload the .xml/.gz/.zip and see sending sources, SPF/DKIM/DMARC results and dispositions in a clear table.