由一位自 1996 年起就从事这项工作的人打造。
在企业网络与安全领域深耕三十年，由一位活跃的讲师亲自呈现，而非一页市场文案。横跨平台的认证，意味着这里的对比是诚实的，而不是为了促成交易。
The chapters lived from inside
These fourteen are also chapters of my own record - each timeline carries a My chapter marker. The full telling lives at the career record.
- Cabletron 与 Enterasys1996 – 2007
- Riverstone Networks2000 – 2002
- Cisco Systems2003 – 2008
- IronPort Systems2004 – 2005
- NetScreen 与 Juniper2009 – 2014
- Extreme Networks2013 – 2014
- FireEye, McAfee and Ixia2015 – 2019
- Pulse Secure2018 – 2019
- Palo Alto Networks2013 – 2015
- F52015 – present
- Fortinet2022 – present
- Netskope2024 – present
- Ping Identity and ForgeRock2025 – present
- Zscaler2026 – present
- Check Point2026 – present
平台，持续教授并保持最新。
What is here
Six sections, built over years rather than assembled for a launch. Every count below is read from the thing itself at build time, so none of them can drift from what you will actually find.
Vendor hubs →
One door per platform: the tools, articles and certification material for that vendor, gathered in one place.
Tools →
Deterministic calculators and explainers for networks, security and identity. They compute in your browser and send nothing anywhere.
138 live
Learn →
Technical articles on the protocols and products behind the tools, written to be read rather than skimmed.
528 articles
Glossary →
Every term and acronym used across this site, defined once and cross-referenced. The thing to open mid-article.
Industry →
Company histories from the beginning of networking to now, including the ones that failed and the ones nobody remembers.
164 companies4 of them turn 50 this year
The Practice →
How the work is actually done rather than how the technology works. Triage, escalation, evidence, handover.
15 of 48 published
Certification guides →
What each exam tests and what to study for it. Free, and useful whether or not you ever book a course.
105 guides
Study guides →
Objective-by-objective walkthroughs for the exams, showing what is covered here and, honestly, what is not.
Training I teach →
Authorized instructor-led courses across four platforms, delivered through Red Education.
Advisory →
Independent judgement on decisions that have not been made yet. Scoped work, written answer, no on-call.
By engagement
About →
Who is writing all of this, what I have done, and why any of it should be trusted.
The career record →
Fifteen chapters from 1996 onward, each told from inside the company it happened in.
Red Education →
The global authorized training centre my courses are delivered through, and the story of how it got there.
为什么在安全工作中本地运行很重要。
当您把配置、抓包或证书粘贴到工具里时，这些数据往往包含机密。在这里，日常工具完全在您的浏览器中运行。您输入的内容从不离开您的设备，因此没有什么可被记录、泄露，或在法庭命令下被交出。
现在就试用工具。
下方的 CIDR 计算器在本地运行。输入网络和前缀，即可看到地址范围、主机数量和掩码。没有任何内容被发送到任何地方。
CIDR 计算器
分析单个 IPv4 CIDR 块：网络、广播、掩码和主机范围。
本地运行，不向任何服务器发送任何内容。