netcat is a network diagnostics toolkit for network engineers, admins and developers. Long-press any address or host name in a result to send it to DNS Lookup, Whois, Ping, MTR, Port Scan, Port Connect or IP Calculator. Recent runs are on the Home tab: tap one to run it again with the same options.
NETWORK INFO
• Your public IPv4 and IPv6 as sites in China see them and as other sites see them
• Where each address is registered, from an IP database inside the app
• Interfaces with their addresses, prefix lengths and MTU; gateways, DNS servers and the routing table
DNS CHECK
• Reachability and latency of your DoH, DoH3, DoT, DoQ and classic UDP / TCP DNS servers
• Any address format, DNS stamps, bulk import and bootstrap IPs, plus a default list of public resolvers to import
• Answers, DNSSEC, TLS version, ALPN, HTTP version and per-phase timing
DNS LOOKUP
• Like dig: the system resolver or any DoH, DoH3, DoT, DoQ, UDP or TCP server
• Common record types, reverse lookups from an IP address, DO / CD / RD flags
• All response sections, EDNS, NSID, EDE and DNSSEC records; dig-style output
WHOIS
• Registration data for domains, IP addresses / prefixes and AS numbers
• RDAP first, classic whois where a registry has no RDAP, following referrals to the registry and registrar
• Registrant, registrar, dates, status, name servers, DNSSEC, network range, organization and abuse contact at a glance; raw responses to expand and export
• Or query any whois or RDAP server of your choice
PING
• ICMP and TCP modes, up to 6 targets in parallel
• A latency bar chart per target that makes spikes and losses obvious
• min / avg / max / sd, P50 / P90 / P99, jitter and loss
• Adjustable interval, timeout, count, payload size and TTL; ping-compatible output
MTR
• Continuous traceroute with per-hop Loss%, Last, Avg, Best, Wrst and StDev
• Every hop's recent rounds on one latency scale: see where delay is added; loss on the path in red, routers that only rate-limit their replies in grey
• Reverse DNS names, IPv4 / IPv6, export in mtr --report format
PORT SCAN
• TCP connect scan of port lists and ranges, like nc -z
• Open, closed and filtered ports with response times and service names
• Long-press a port to connect to it
PORT CONNECT
• Connect to any host and port over TCP, UDP or TLS, like nc
• Name lookup, TCP and TLS handshake times; TLS version, cipher suite, ALPN and the certificate chain with its trust verdict
• Send text or hex and read the replies as text or a hex dump
IPERF3
• Client and server roles, compatible with standard iperf3 in both directions
• TCP / UDP, upload / download, parallel streams, UDP bitrate
• Per-second throughput chart, sender / receiver rates, retransmits, UDP jitter and loss
IP CALCULATOR
• IPv4 and IPv6 subnets: network, netmask, wildcard, broadcast, host range and address counts
• Address type (private, CGNAT, link-local, documentation, NAT64…) and the reverse DNS zone
PRIVACY
No account, no ads, no analytics, no data collection.
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