Networking, DNS & Domains

11 In-Browser Tools

IPv4/IPv6 subnet calculators, CIDR ranges, SPF/DMARC validators, DNS records, and email deliverability. Zero cloud uploads — runs locally on your machine in volatile memory.

Subcategories:

IPv4 Subnet & CIDR Prefix Calculator

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

ip-addressing

SPF & DMARC DNS Record Validator

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

email-dns

IPv6 Subnet Calculator & Full 32-Hex Expander

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

ipv6

DNS Record Lookup & Master Zone Simulator (A, AAAA, MX, TXT)

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

dns

Email Deliverability & Disposable Domain Checker

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

IPv4 Subnet Mask & Wildcard Mask Calculator

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

ip-routing

SPF & DMARC DNS Record Generator

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

email-auth

CIDR Subnet Calculator & IPv4 Address Range Generator

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

IPv6 Address Expander & RFC 5952 Compressor

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

Bandwidth Download & Upload Duration Calculator

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

bandwidth

Common Network Port Lookup & TCP/UDP Directory

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

ports