Cyber security and software, UK
Cyber Security and Software, Led by Senior Practitioners.
We build websites, mobile apps and software that take the tedious work off your team, and we design, test and defend the networks underneath them. We take on a select number of engagements, and a senior practitioner leads every one from the first call to the final report.
What We Do
01
Websites, Mobile Applications and Bespoke Software
Fast websites, iOS and Android apps and bespoke software that takes the tedious, repetitive work off your team.
Read more about Websites, Mobile Applications and Bespoke Software
02
Network and Identity Design
Zero Trust architecture, Microsoft Entra ID, privileged access, segmentation and IPv6, designed new or reviewed against what you run today.
Read more about Network and Identity Design
03
OT and Critical Infrastructure Security
Purdue model segmentation, ICS hardening reviews and OT risk assessment, from a practice rooted in critical infrastructure.
Read more about OT and Critical Infrastructure Security
04
Digital Forensics and Incident Response
Forensic investigation, containment and recovery on retainer or as planned work, and the readiness that decides the first hour.
Read more about Digital Forensics and Incident Response
05
Penetration Testing and Security Assessment
Infrastructure, Active Directory, cloud and web application testing, scoped to the risks you care about and reported so they get fixed.
Read more about Penetration Testing and Security Assessment
06
Governance, Risk and Compliance
ISO 27001, Cyber Essentials and NIS2 readiness, risk management and fractional security leadership.
Read more about Governance, Risk and Compliance
07
Training
Networking and security training for IT teams, leadership and staff, and revision support for CCNA and Network+.
Read more about Training
Why Greywell
Our practitioners' backgrounds include critical infrastructure, digital forensics and incident response. We are selective about the engagements we take, so senior practitioners stay on the work instead of handing it down a chain.
Every engagement is scoped and contracted before work starts: what is in scope, what it costs, who does the work and when you will have the results. Reports are written for the engineers who will act on them and the board that has to decide.
Dealing with an incident? Email security@greywellcyber.com with URGENT in the subject line. Retained clients use the route in their contract. More on digital forensics and incident response.
Free Network Tools
Built and maintained by us, free for anyone to use. The calculators and generators run in your browser and need no account. Try 10 quiz questions without one; a free account opens the full quiz and saves your progress.
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IPv4 and IPv6. Network, broadcast, host range, mask and wildcard at a glance.
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Split one IPv4 block into named subnets of different sizes, largest first, with the spare space shown.
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Practice questions across twelve topics, from subnetting maths to OT risk. Try 10 questions without an account; a free account saves your progress.
Also: the route summariser, the security headers checker and our guides to IPv4 Network Design and IPv6 Design .