Frequently Asked Questions

What is Network Tools Online?

Network Tools Online is a free collection of browser-based networking utilities — subnet calculator, CIDR range expander, MAC vendor lookup, UA parser, DNS lookup, and port reference — that run entirely in your browser.

Are these tools really free?

Yes. All tools are completely free with no hidden fees, no API keys, no premium tiers.

Does my IP plan or MAC list get sent to a server?

No. Subnet math, CIDR expansion, MAC lookup, UA parsing, and port reference all run locally in your browser. The only network call is from the DNS Lookup tool — and it only sends the domain you type to Cloudflare's public DoH resolver.

Which DNS resolver is used?

Cloudflare's public DNS-over-HTTPS resolver at cloudflare-dns.com. We bypass your operating system's local resolver to give you a fresh view of public DNS.

Why does the MAC lookup say "Unknown vendor"?

This tool ships with a curated subset of the IEEE OUI registry (top ~200 vendors). Rare assignments, very recent OUIs, or locally administered / privacy MACs (iOS / Android random MAC) may not be in the dataset.

Can the Port Reference tool scan a port?

No. Browsers cannot open arbitrary TCP sockets. This tool tells you what service a port is assigned to (per IANA), not whether the port is reachable.

Does this support IPv6?

Subnet calculations are IPv4-only. The DNS Lookup tool can query AAAA records for IPv6 addresses; UA Parser, MAC Lookup, and Port Reference are protocol-agnostic.

How accurate is the subnet calculator?

The calculation uses the ip-num library, a TypeScript implementation that's widely used in production. Network, broadcast, mask, and host counts are computed exactly — no off-by-one risk.

Can I use these tools on my phone or tablet?

Yes. All tools are fully responsive and work on any modern mobile browser.

Do you store any of my data?

We do not store tool input. We may collect anonymized analytics (page views, browser type) to improve the site.

How do I report a bug or suggest a new tool?

Please use our Contact page. We read every message and aim to respond within two business days.