Network Tools
Subnetting, DNS, latency, and other networking calculators and lookups.
22 tools
Look something up6
BGP AS Lookup
Free BGP AS lookup. Enter an ASN or IP to get the AS holder, RIR, country, abuse contact and every announced IPv4/IPv6 prefix. Live RIPEstat data.
DNS Record Checker - Verify SPF, DKIM, DMARC & More
Look up A, AAAA, CNAME, MX, TXT, NS, SOA, SRV and CAA records for any domain. Parses SPF and DMARC, detects your providers and grades DNS health.
IP Geolocation Lookup
Look up any IPv4 or IPv6 address to find its city, country, ISP, ASN and organization, plotted on an interactive map. Free, instant, no signup.
MAC Address Lookup
Free MAC address lookup. Paste any MAC or OUI to identify the device vendor from 38,000+ IEEE records. Bulk and batch lookup, all formats, no signup.
Port Reference
Search 5,985 TCP and UDP ports by number, service or category. Get the protocol, what runs there, RFC references and whether it is safe to expose.
WHOIS Lookup
Free WHOIS lookup tool. Query domain registration details including registrar, owner, nameservers, expiration dates, and DNSSEC status for any domain name.
Diagnose a connection5
Network Investigation Lab
Check whether an IP is public, RFC 1918 private, loopback or reserved, and compare two DNS snapshots for records added, removed or TTL-changed.
PCAP Analyzer
Analyze a .pcap or .pcapng capture in your browser. Protocol breakdown, top talkers, conversations and TCP flags. Nothing is uploaded.
Redirect Chain Checker
Trace every hop in a URL's redirect chain. See status codes, timing, loops, HTTPS downgrades and SEO issues, with fixes for flattening chains to one hop.
URL Expander
Expand any shortened URL and see the full redirect chain, status codes, shortener service and a safety score - without clicking it. Free, no signup.
What Is My IP
See your public IP address instantly, with approximate location, ISP, and browser details. A fast, private IP lookup with no sign-up required.
Addressing & subnetting2
Free IP Subnet Calculator - IPv4 & IPv6 CIDR Tool
Calculate subnet masks, network addresses, broadcast addresses, and usable host ranges for IPv4 and IPv6. CIDR notation support.
IPv4 to IPv6 Converter
Convert IPv4 to IPv6 instantly: IPv4-mapped, hex and 6to4 forms. Or paste IPv6 to expand, compress, extract the IPv4 and identify it. Free, in-browser.
Command builders3
netstat Command Builder
Build netstat and Get-NetTCPConnection commands to find the process using a port and list connections.
Network Reset Command Builder
Build Windows network reset commands - winsock, TCP/IP, flush DNS.
Traceroute Command Builder
Build tracert, pathping, traceroute and mtr commands to trace the path to any host.
Design & capacity4
Firewall Rule Logic Simulator
Free interactive firewall rule simulator. Build rulesets, craft test packets, and trace rule matching with stateful/stateless inspection modes.
Network Latency Calculator
Calculate network latency between two cities, estimate distance from a ping RTT, and compute file transfer time. Free fiber latency calculator.
TCP Window Size Calculator
Calculate TCP throughput, bandwidth-delay product and optimal window size from bandwidth and RTT. Free BDP calculator with MSS and packet-loss math.
Wireless Security Architecture Planner
Plan a Wi-Fi deployment: WPA protocol choice, 802.11 standard, antenna types, an access point count estimate and a security hardening checklist.
More tools2
SNMP OID Lookup & snmpwalk Builder
Free SNMP OID lookup: search 359 verified OIDs by number or name, then build snmpwalk, snmpget and snmpbulkwalk commands for v1, v2c and v3.
VoIP Bandwidth Calculator
Work out VoIP bandwidth per call and for every concurrent call: codec, packet size, Ethernet, VPN and cRTP overhead, plus an estimated MOS score.