network/ops
Free, Browser-Based Network & IP Utilities — Subnet, CIDR, MAC, UA, DNS Lookups
Available Tools
IPv4 Subnet Calculator
Calculate network address, broadcast, mask, and host count for any IPv4 CIDR.
CIDR to IP Range
Expand any CIDR block into its start address, end address, and total count.
MAC Address Lookup
Identify the manufacturer (OUI) of any MAC address from the IEEE registry.
User Agent Parser
Extract browser, engine, OS, and device info from any user-agent string.
DNS Record Lookup
Query A, AAAA, CNAME, MX, TXT, NS and SOA records for any domain.
Port Reference
Look up the standard service for any TCP/UDP port number (IANA registry).
Why Use Network Tools Online?
Accurate Subnet Math
IPv4 subnet, CIDR, and broadcast calculations done with the well-tested ip-num library — no off-by-one mistakes that take down a network.
Instant Lookups
MAC vendor, user agent, and port reference data is bundled into the page. Lookups happen with zero network latency.
Completely Free
Every tool on this site is free to use with no account required, no credit system, and no API key. Bookmark it for daily ops work.
Fresh DNS Queries
DNS lookups go straight to Cloudflare's public DoH resolver from your browser, bypassing your local DNS cache for an accurate live view.
Built for Operators
Each tool exposes the fields ops engineers actually need — copy-paste buttons, monospaced output, and zero clutter.
Works on Any Device
Fully responsive and optimized for desktop, tablet, and mobile. Use any modern browser — no installer required.
How to Use Our Network Tools
Choose a Tool
Pick what you need — subnet math, CIDR expansion, MAC vendor lookup, UA parsing, DNS query, or port reference.
Enter Your Input
Paste a CIDR, MAC address, UA string, or domain. Results appear live as you type for most tools.
Copy & Move On
Inline Copy buttons grab any field. Open multiple tools in tabs to chain network research.
Who Uses Network Tools Online?
Verify subnet boundaries before configuring routers, expand CIDRs for firewall rules, and look up MAC vendors during inventory audits.
Size VPC and security-group CIDRs accurately, validate DNS propagation from outside your local cache, and decode service ports from log files.
Map mystery devices on your LAN via MAC OUI, group access logs by browser via UA parsing, and confirm DNS records during incidents.
Practice subnet math with instant feedback, see how CIDR notation maps to address ranges, and reference IANA port assignments.
Frequently Asked Questions
Are these network tools really free?
Yes, completely free. There are no premium tiers, no credits to purchase, and no account required.
Where is the DNS Lookup query sent?
To Cloudflare's public DNS-over-HTTPS resolver at cloudflare-dns.com. No other DNS server is involved — not your ISP, not our backend.
Why does the MAC lookup say "Unknown vendor"?
This tool ships with a curated subset of the IEEE OUI registry (top ~200 vendors). Rare or very recent OUI assignments may not be in the bundled dataset.
Does this tool support IPv6?
Subnet calculations are IPv4-only. DNS Lookup supports AAAA records to query IPv6 addresses; UA Parser, MAC Lookup, and Port Reference are protocol-agnostic.
Can the Port Reference tool actually scan a port?
No. Browsers cannot open arbitrary TCP sockets. This is a reference tool — it tells you what service uses a port, not whether the port is reachable.
Can I use these tools on my phone or tablet?
Yes. All tools are fully responsive and work on any modern mobile browser.