COMPUTER CENTER / UTILITIES
Test a new web server before changing DNS
Compare a website’s current server with a proposed public IP before changing DNS. Preserve the hostname and verify HTTPS on both connections.
Migration rehearsal
Compare a website’s current server with a proposed public IP before changing DNS. Preserve the hostname and verify HTTPS on both connections.
How to use this tool
Enter the website URL and the proposed server’s public IP. The check requests the same URL from the current DNS address and from the new address while keeping the original Host header and TLS hostname. Compare status codes, headers and certificate results.
Reading the results
This check does not modify DNS and does not copy files. The new server needs a valid certificate for the requested hostname; verification is never disabled. A matching response cannot prove that databases, scheduled jobs or every application route migrated correctly, so test those separately before switching traffic.
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.