All tools
Every tool is free, needs no account, and runs a live query when you press the button.
Check a DNS record across 85 public resolvers
Delegation, glue, lame nameservers, SOA serials, reachability, DNSSEC chain
All DNS records for a domain in one query
IPv4 addresses a hostname resolves to
IPv6 addresses for a hostname
Alias target of a hostname
Authoritative nameservers for a domain
All TXT records — SPF, verification, and more
Zone serial, refresh, and primary nameserver
Which certificate authorities may issue for a domain
Service records for SIP, XMPP, and more
Is a zone signed, and does it validate?
Same query against Google, Cloudflare, Quad9, OpenDNS side by side
Email Deliverability Tools
SPF, DKIM, DMARC, MX, and mail-server checks →Mail servers and priorities for a domain
Validate SPF syntax and count the 10-lookup limit live
Build a correct SPF record with provider presets
Find and validate DKIM keys — selector discovery included
Policy, alignment, and why Gmail may reject you
Create a DMARC record with a safe rollout policy
Is your IP or domain on a DNS blocklist?
Can your mail server be reached on ports 25/465/587?
Decode Received chains, SPF/DKIM/DMARC results, and delays
Is SMTP TLS policy published and valid?
Brand logo record status for your domain
SPF + DKIM + DMARC + MX + PTR on one screen
IP & Network Tools
IP, reverse DNS, ports, ping, and subnets →Your public IPv4/IPv6 and request headers
Hostname behind an IP — required for mail servers
CIDR ranges, masks, and usable hosts
Is a single TCP port open on a host?
ICMP reachability and latency from our server
Network path from our server to a host
Which network announces an IP, via RIPEstat
Domain Tools
WHOIS, domain age, redirects, and headers →Everything at once: DNS, MX, SPF, DKIM, DMARC, DNSSEC, SSL, expiry
Registrar, dates, and nameservers for a domain
How old is a domain, and when does it expire?
Follow a URL through every redirect hop
Response headers a server actually sends
HSTS, CSP, and friends — graded
Web Utilities
Generators and converters for daily server work →Bcrypt htpasswd lines for basic auth
Permission bits ↔ octal, with explanations
Build and read crontab schedules
Strong random passwords, locally generated
SHA-256/384/512 and MD5-alternative digests in your browser
Text ↔ Base64, UTF-8 safe
Percent-encoding both directions
Pretty-print, minify, and validate JSON
Inspect JWT header and payload — locally, no signature check
Test JavaScript regular expressions live