Practical tools from the daily work of a network and security engineer — free, no sign-up, right in your browser.
Subnet Calculator (IPv4 & IPv6) with CIDR Summarization
Calculate network, mask, hosts and wildcard, summarize IP lists to CIDR and export as FortiGate, Palo Alto or Cisco configuration.
Email Security Check: SPF, DKIM & DMARC
Check your domain's SPF, DKIM, DMARC and MX — with a score, explanations and ready-made DNS records. SPF and DMARC generators included.
WiFi QR Code Generator
Guests scan and connect. Print-ready sign as PNG, SVG or straight to the printer — your password never leaves your device.
NIS2 Check: Is My Company Affected?
Find out in three steps whether your company falls under Germany's NIS2 act — and which obligations (BSI registration, reporting, risk management) apply.
Why these tools?
I have worked with firewalls, network access control and enterprise networks for more than 11 years — and I use these tools myself every day. So they are built the way I want them:
- No sign-up, no ads. Just open and use.
- Privacy-friendly. All calculations run in your browser. The email check only queries public DNS records; Digitriva stores nothing.
- Practical. Exports for FortiGate, Palo Alto and Cisco, ready-to-copy DNS records, print-ready QR signs.
Got a problem a tool alone can’t solve? Get in touch — the first consultation is free.