Network & IP
Calculate IPv4 and IPv6 subnets, convert netmasks and CIDR, aggregate ranges, validate IPs and normalize MAC addresses without scanning the network.
Explore tools
IPv4 subnet and netmask calculator
Calculate IPv4 subnet boundaries and usable endpoints, or convert a netmask and prefix.
IP range to CIDR
Turn an inclusive IPv4 address range into the smallest exact list of CIDR blocks.
Aggregate CIDR blocks
Reduce an IPv4 CIDR list without changing its address coverage.
IPv4 number converter
Convert one IPv4 address between dotted decimal, unsigned integer and 32-bit binary.
IPv6 expand and compress
Convert one IPv6 address to canonical, expanded and colon-free 32-digit forms.
IPv6 subnet calculator
Find the exact start, end and size of one IPv6 prefix.
MAC address normalizer
Convert MAC addresses between colon, hyphen, Cisco dotted and plain formats, including short and Python hex octets.
IP address validator
Validate one IPv4 or IPv6 address per line and export the valid entries.
IP in CIDR checker
Check a list of IP addresses against one IPv4 or IPv6 CIDR and export matching values.
IPv4 CIDR set subtraction
Subtract excluded networks from an IPv4 allocation and save the exact remaining CIDR blocks.
Nmap XML open-port report
Turn a saved Nmap XML scan into an Excel workbook and CSV of host addresses and open ports.
Find matching SSH known-host records
Search a local known_hosts file for a supplied host and port, with match explanations and supported public-key fingerprints.
Read DMARC aggregate observations
Read local RUA XML or gzip batches with exact weighted observations, complete declared policy/authentication records and explicit duplicate-report handling.
Inspect supplied certificate signature links
Verify every exact-name RSA-SHA256 link in local PEM certificates, preserve full evidence, and order a uniquely connected supplied chain.
Explain declared route selection
Compare a declared IPv4/IPv6 route table against destinations; retain longest-prefix and metric decisions, equal-rank candidates, terminal actions and every comparison.
Choose the right tool
Define the required address set before choosing a prefix. Convert exact ranges to CIDR, compare coverage after aggregation and test excluded neighbors. These tools perform local arithmetic; they do not scan networks, look up device owners or apply access rules.