Network

Calculate network address, broadcast, host range and masks from an IPv4 address and CIDR prefix.

Convert a CIDR block to its IP range and total addresses, or find the smallest CIDR covering a range.

Convert between dotted subnet mask, CIDR prefix length and wildcard mask.

Get the total address count and the list of CIDR blocks that exactly cover a start-to-end IP range.

Convert an IPv4 address to its IPv4-mapped IPv6 forms, full notation and 6to4 prefix.

Expand a compressed IPv6 address to full form and compress a full one back down.

Normalize a MAC address into colon, hyphen and Cisco dot notations in upper and lower case.

Convert an IPv4 address to dotted binary, a 32-bit decimal integer and hexadecimal.

Searchable reference of common TCP and UDP port numbers and their services.

Searchable reference of DNS record types and what each one does.

Identify an IPv4 address class (A-E) and whether it is private, public, loopback or reserved.

Searchable reference of common HTTP request and response headers.

Paste a User-Agent string to detect the browser, operating system and device type.

Convert a subnet mask or CIDR prefix into the inverse wildcard mask used in Cisco ACLs.

Compress a full IPv6 address to its shortest RFC 5952 form, or expand it back out.

Estimate how long a file will take to download based on its size and your connection speed.