Network & Web Tools
Look up IPs, DNS records, and site metadata. 7 tools
Lookups that answer questions about a domain, an address or a page: which records a domain resolves to, who registered it, what your own public address looks like from outside, and what metadata a page is actually serving.
These are the exception on this site: a lookup has to leave your device, because the answer lives on someone else's server. Each page says so plainly. Your query is sent, no files are uploaded, and nothing is stored.
All 7 network & web tools
My IP & Geolocation
See your public IP address and its approximate location.
DNS Lookup
Resolve A, AAAA, MX, TXT, and NS records for any domain.
Website Meta / SEO Tag Checker
Inspect a page's title, meta description, and Open Graph tags.
What's My User-Agent
Display and parse your browser's user-agent string.
IP Subnet Calculator
Calculate network, broadcast, and host ranges from CIDR notation.
HTTP Headers Checker
Inspect the response headers any URL returns.
WHOIS Lookup
Look up domain registration details from WHOIS servers.
What to know before you pick one
These tools have to use the network, and that is unavoidable
Most of this site works without sending anything anywhere. This category cannot: asking who owns a domain, what a hostname resolves to, or which headers a server returns are questions only that server or registry can answer. So the lookups here do leave your browser, and each tool says so on its own page. It is the honest trade for a question that has no local answer.
DNS answers are cached, so “wrong” often means “old”
A record you changed minutes ago can still show the previous value, because resolvers hold answers for the length of time the record itself specifies. Different resolvers expire at different moments, which is why two people checking the same domain can honestly see different results. If a change has not appeared, the usual answer is that the old value has not expired yet rather than that the change failed.
Reading headers tells you more than reading the page
The response headers carry the things that decide behaviour and are invisible on screen: whether a redirect happened and whether it was permanent, how long the response may be cached, which security policies apply, and what the server claims the content is. When a page behaves differently in two places and looks identical in both, the difference is almost always here.
Subnet arithmetic is where confident people slip
The usable host count is two fewer than the address count, because the first address identifies the network and the last is the broadcast address. A /24 therefore holds 256 addresses and 254 usable ones. Off-by-two errors here produce configurations that work in testing and fail on the edges of the range.
What a registry lookup will and will not tell you
Domain records show when a name was registered, when it expires and which registrar holds it — genuinely useful for judging whether a site is new, and for finding out who to contact about one. What they mostly no longer show is a person. Privacy services and data-protection law mean the owner is usually replaced by a proxy address, so treat an absent name as the normal case rather than as something suspicious.
An IP address is a rough location, not an address
Geographic lookups resolve to the network that holds the address, which is often a data centre in a different city from the person using it, and is routinely wrong for mobile networks and anyone on a VPN. It is reliable enough for choosing a language or a nearby server, and it is not reliable enough to make a decision about an individual.