Network

Look up the Autonomous System Number (ASN) and owning organization for any public IP address. Free online ASN lookup tool.

Check a DNS record against Google, Cloudflare, Quad9, and OpenDNS public resolvers simultaneously to see if a change has fully propagated. Free online DNS propagation tool.

Look up A, AAAA, MX, TXT, NS, or CNAME DNS records for any domain in real time. Free online DNS lookup tool.

Check whether an IPv4 address is listed on major public DNSBL/RBL spam blocklists (Spamhaus, SpamCop, Barracuda). Free online IP reputation checker.

Measure the server-side HTTP round-trip time to any website — a browser-friendly substitute for ping. Free online latency checker.

Check your IP address or query any IPv4/IPv6 address to find its geographic location, ASN, and proxy status.

Determine if an IP address belongs to a known Proxy, VPN, Tor exit node, or data center.

Perform a reverse DNS lookup to find the hostname associated with any IPv4 or IPv6 address. Quick, accurate, and free PTR record check.

Resolve a shortened URL (bit.ly, t.co, tinyurl, and more) to its final destination server-side before clicking it. Free online link expander.

Instantly find out your public IPv4 or IPv6 address, geographic location, ASN, and proxy status.

Merge a list of CIDR blocks into the minimal set of covering supernets. Free and runs entirely in your browser.

Convert a CIDR block (e.g. 10.0.0.0/24) into its network, broadcast, and usable IP range instantly. Free and runs entirely in your browser.

Sort a list of IPv4 addresses numerically (not alphabetically), with optional deduplication and descending order. Free and runs entirely in your browser.

Convert a dotted-decimal IPv4 address to hexadecimal notation, or decode a hex value back to an IP address. Free and runs entirely in your browser.

Convert a first-last IP address range into the minimal set of covering CIDR blocks. Free and runs entirely in your browser.

Validate an IPv4 address and classify it as public, private, loopback, link-local, multicast, or reserved. Free and runs entirely in your browser.

Convert a dotted-decimal IPv4 address to its 32-bit binary octet representation, or back again. Free and runs entirely in your browser.

Compress a full-form IPv6 address to its shortest valid :: representation. Free and runs entirely in your browser.

Expand a compressed IPv6 address (using ::) to its full 8-group form. Free and runs entirely in your browser.

Validate an IPv6 address and classify it as global unicast, unique local, link-local, multicast, or loopback. Free and runs entirely in your browser.

Convert between a dotted-decimal subnet mask (255.255.255.0) and CIDR prefix notation (/24) instantly. Free and runs entirely in your browser.

Convert an internationalized domain name (IDN) with non-ASCII characters to its ASCII Punycode (xn--) form. Free and runs entirely in your browser.

Normalize a MAC address between colon, hyphen, Cisco-dot, and plain notation instantly. Free and runs entirely in your browser.

Decode a Punycode (xn--) ASCII hostname back to its original Unicode internationalized domain name. Free and runs entirely in your browser.

Generate a random IPv4 address, optionally constrained to a specific CIDR range. Free and runs entirely in your browser.

Generate a cryptographically random MAC address, with an optional locally-administered or multicast bit. Free and runs entirely in your browser.

Generate a firewall-rule-ready list of ports from single values and ranges, with automatic compression. Free and runs entirely in your browser.

Look up the meaning and category of any HTTP status code, from 100 to 599. Free and runs entirely in your browser.

Look up a MIME type from a file extension, or find the file extension(s) for a MIME type. Free and runs entirely in your browser.

Look up the standard service name for a well-known TCP/UDP port, or search ports by service name. Free and runs entirely in your browser.