NETWORK UTILITIES
Tools for the troubleshooting desk.
Small, practical checks for network engineers. Calculations run in your browser; DNS lookups run only when you ask.
CONNECTION CHECK
What does the internet see?
Check your public network details, local time, and a local-only browser signature. Nothing is collected until you choose to run the check, and results are not stored by Cyber Runbook.
Your IP address is returned only to your browser for this request. It is not saved by this site.
- Public IP
- -
- Network / ASN
- -
- Location
- -
- Local time
- -
- Time zone
- -
- Browser signature local only
- -
- Browser
- -
OFFLINE CALCULATION
IPv4 subnet calculator
Enter an IPv4 address and CIDR prefix. Nothing leaves your browser.
- Network
- Subnet mask
- Broadcast
- Usable hosts
- Usable range
PUBLIC RESOLVER CHECK
DNS propagation check
Compare answers from Cloudflare and Google public recursive resolvers. This is a resolver check, not a guarantee for every DNS server worldwide.