Free Network & IT Tools
Subnet calculator, DNS lookup, SSL checker, password generator, email authentication tools, and more. Built for sysadmins and network engineers.
Network
Show My IP
Display your public IP address, ISP, and ASN
IP Geolocation
Find the geographic location of any IP address
Subnet Calculator
Calculate network addresses, ranges, and subnets from CIDR notation
Bandwidth Calculator
Convert and calculate bandwidth, transfer times, and data sizes
MTU Calculator
Calculate optimal MTU size accounting for encapsulation overhead
MAC Address Lookup
Find the vendor/manufacturer from a MAC address
Speed Test
Test your internet download and upload speed
Server Status Checker
Check if a website or server is up and reachable
Port Reference
Common network ports and their services
DNS
SPF Builder & Checker
Build and validate SPF records for your domain
DKIM Checker
Verify DKIM records and key configuration
DMARC Builder & Checker
Build and validate DMARC policies for email authentication
Email Deliverability Tester
Score your email setup for deliverability issues
Email Header Analyzer
Trace email delivery path, detect delays, and check authentication results
Blacklist Checker
Check if an IP or domain is listed on major email blacklists (DNSBL)