Networking, DNS & Domains

IPv4/IPv6 subnet calculators, CIDR ranges, SPF/DMARC validators, DNS records, and email deliverability.

IPv4 Subnet & CIDR Prefix Calculator

Calculate network address, broadcast address, netmask, wildcard mask, and usable host ranges for CIDR /1 to /32.

Validate and analyze DNS SPF and DMARC TXT records for syntax validity, DNS lookup counts, and email deliverability.

Expand compressed IPv6 addresses and calculate CIDR network prefixes and host capacity.

Generate and inspect standard RFC DNS zone records and CLI dig query commands.

Validate email syntax, detect disposable temporary domains, and flag generic role accounts.

Calculate network address, broadcast IP, usable host ranges, CIDR prefix, and Cisco wildcard masks.

Generate standards-compliant TXT records for SPF email authorization and DMARC anti-spoofing policies.

Calculate network address, broadcast address, netmask, wildcard mask, first/last usable host, and total usable hosts from CIDR.

Expand compressed IPv6 addresses into full 32-hex-digit 8-hextet format or compress full IPv6 using RFC 5952 canonical rules.

Calculate estimated download and upload durations for files across internet connection speeds with TCP/IP overhead.

Searchable directory of standard IANA and well-known TCP/UDP network ports, protocols, and service descriptions.