Number verification and network tools
Choose a tool or search by name: phone, IP, DNS, card, IBAN, PESEL.
Phone numbers and IP calculations stay in this browser. We do not put input in links, QR codes or browser storage. DNS sends only the domain and record type to this site and the system resolver. My connection sends an empty request to our server. Results are not saved by the tool; ordinary hosting access logs may record the request IP.
No matching tools.
Phone number validator
Country, format and number type. No carrier or owner lookup.
IPv4 / IPv6 / CIDR calculator
Network, mask, address range and conversions.
Domain and DNS records
A, AAAA, MX, TXT, NS and CNAME records. Requires a network connection.
My connection
Check the IP address visible to this server and information reported by your browser. The check runs only when you click. Browser details are processed locally.
How current are the directories?
Dates below describe the bundled phone metadata snapshot and the bank export publication date. Review intervals: phones 90 days, banks 30 days. Being within the interval does not guarantee that no newer source exists. An overdue directory does not prove that a number is invalid.
Does a valid phone number identify the current carrier?
No. Validation checks a numbering plan, not activation or ownership. Numbers can be ported between carriers. The bundled libphonenumber-js metadata may become outdated; it needs periodic updates.
How are subnet ranges calculated?
The network is the address AND the mask. The address count is 2^(bits − prefix). IPv4 /31 has two endpoint addresses on a point-to-point link; /32 has one. IPv6 has no broadcast; its address count is not a count of assignable hosts. Zone IDs and IPv6 prefixes written as masks are not accepted.
Why can DNS results differ?
Answers depend on time, resolver cache and location. A missing answer is not proof of an available domain. We query one selected type, without fetching the website or following HTTP redirects. The service allows up to 12 requests per minute per connection address.