COMPUTER CENTER / UTILITIES
Domain & network tools
Free domain, DNS, email and network diagnostics. Check SMTP, PTR, DKIM, SPF, TLS, redirects, reverse IP and IPv4/IPv6 connectivity.
Domain report
DNS records and registration details in one report.
How to use this tool
Reading the results
Tools index
23 utilitiesDNS changes
Compare a saved DNS snapshot with a fresh lookup.
DNS lookup
A, AAAA, MX, TXT and other DNS records.
DNS comparison
Compare answers from two public resolvers.
WHOIS / RDAP
Domain and IP registration records.
Reverse DNS / PTR
Reverse DNS and forward-confirmed hostnames.
Sites on this IP
Find indexed domains sharing an IPv4 address.
Mail journey
Read the route and reported authentication of an email.
SPF map
Explore SPF include and redirect dependencies.
Email DNS
MX, SPF and DMARC configuration.
SMTP check
Mail server banner, EHLO and TLS negotiation.
DKIM lookup
Public signing keys for a named selector.
Mail transport policies
MTA-STS policy and TLS reporting records.
Migration rehearsal
Check a new server before switching DNS.
IPv4 / IPv6
Compare a website over both address families.
Security contact
Find and review a site’s security.txt contact file.
Redirect trace
Follow the HTTP redirects of a web address.
Security headers
Review browser security policies in the response.
ASN & routes
Find the route prefix and autonomous system for an IP.
HTTP & TLS
HTTP headers and TLS certificate details.
TCP ping
Connection times on port 80 or 443.
Subnet calculator
Address ranges and subnet masks for IPv4 and IPv6.
My IP & connection
Your IP, network and proxy indicators.
DNS answers come from public resolvers. Registration data comes from the relevant registry. Results reflect the time and location of each check.
Visits and checks are recorded for site administration and abuse prevention.