Firewall
Palo Alto Firewall Reference
Security policy structure, NAT ordering, and the App-ID and Content-ID behaviour that decides whether a rule matches the way you expected.
13 live · 5 free tools · no signup
Network tools, uptime monitoring and automation — I AM TAC
5 free network tools — IPv4/IPv6 subnetting, vendor CLI and timezone planning. Plus uptime monitoring, 2 Android apps, an extension and 12 write-ups.
No account for any of the free tools. The subnet, IPv6 and timezone calculators do their arithmetic in your browser, so nothing you type into them is transmitted or stored.
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Privacy
Nothing you type leaves your browser
The IPv4, IPv6 and timezone tools do their arithmetic client-side. The addresses in your address plan are never sent to a server, so there is nothing on our side to store, leak or subpoena.
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Free
No account, no limit
No trial, no usage cap and nothing to sign in to.
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Vendor
Real vendor syntax
Cisco IOS, Palo Alto and Fortinet output you can paste straight into a change window.
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Alerts
Alerts that fire once, not forever
Monitoring emails you on each transition — once when a target goes down, once when it recovers — instead of every five minutes while you are already fixing it. TLS expiry gets a warning before it bites.
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Practical
Built for the on-call hour
Written to be useful at 3am, not to demo well.
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Theme
Dark by default
Light and system themes too, remembered across every subdomain.
Everything, at a glance
13 live of 19 projects, grouped into 6 categories. Drag any row sideways, or use the arrows.
Business
3 / 4
Products built to run in production.
Nothing in this category.
Mobile Applications
2 / 4
Android utilities you can install today.
Nothing in this category.
Browser Extensions
1 / 3
Privacy and productivity, inside the browser.
Nothing in this category.
Study Section
0 / 1
Structured learning paths, in progress.
Nothing in this category.
Free Network Tools
5
No signup, no limits, nothing stored.
Nothing in this category.
Game Section
3
Small browser games. No install, no account.
Nothing in this category.
Browse by category
Five categories, 19 projects. Arrow keys move between tabs; the slider takes arrow keys, swipe and drag.
Appearance
Your choice is kept in your browser’s local storage, never in a cookie and never sent to us. Every I AM TAC tool reads the same key, so setting it here sets it everywhere.
This site follows your system light or dark setting. Choosing a theme manually needs JavaScript, which is currently unavailable — everything else on this page works without it.
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Accent
Dark
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Screenshots
Select any image to view it full size.
Field notes
The 6 most recent of 12 write-ups from real troubleshooting: captures, configs and the fixes that actually worked.
Email
Latest
6 min
Whitelisting the Alert Sender Domain So Monitoring Email Actually Arrives
Downtime alerts are worthless in a spam folder. How to whitelist the sending domain in Google Workspace, Microsoft 365 and common gateways.
AWS
12 min
Troubleshooting AWS Transit Gateway and Fortinet Routing: The Case of the Missing Session
A "Denied by forward policy check (policy 0)" that was not really a policy problem at all. Tracing asymmetric return traffic through a Transit Gateway.
Lab
7 min
Fixing the PNETLab Wireshark "Access Denied" Error
Why the capture helper refuses to attach, and the permission and path fixes that get packet capture working again inside PNETLab.
Lab
5 min
PNETLab Cisco IOU License Fix Utility
A clean keygen script for /opt/unetlab/addons/iol/bin/ so Cisco IOU nodes start instead of failing their licence check.
Interview
15 min
VPN Interview Questions and Answers: Core IPsec Architecture
Phase 1 versus Phase 2, IKEv1 against IKEv2, NAT-T, PFS and the follow-up questions interviewers actually ask after the textbook answer.
Cloud
18 min
Mastering Amazon Web Services: An Architectural Deep Dive
How cloud rewrote the capacity-planning job network engineers used to do, and the VPC, routing and gateway model that replaced it.
Read all articles
6 more write-ups
Click here
Reference library
Longer reference material. Opening one asks for an email address and sends a one-time code — there is no password to invent, and no account is created.
Firewall
Firewall Rules Guide
How to order, name and review firewall rules so a ruleset stays auditable: least privilege in practice, shadowed rules, and cleanup that does not cause an outage.
Cloud
AWS Certified Advanced Networking Slides
Study slides for ANS-C01: VPC design, Transit Gateway routing, hybrid connectivity over Direct Connect and VPN, and DNS resolution across accounts.
By the numbers
5
Free tools
No signup, no limit
13
Live projects
9 on the web
12
Articles
Plus 3 reference documents
138,741
Visits
One counter, nothing else recorded
Common questions
Short answers, all true of the code as it actually stands.
Are the network tools really free?
Yes. The IPv4 and IPv6 calculators, the route and command generator and the timezone converter are free with no usage limit, no trial and no account. The site is funded by advertising.
Do I need an account to use them?
Not for the calculators and generators - they run in your browser, so there is nothing to sign in to. An email address is needed only for two things: the uptime monitoring dashboard, and opening a document in the reference library. Both use a one-time code sent by email rather than a password you have to invent and store.
Which vendors does the command generator support?
It produces static route and interface configuration in Cisco IOS, Palo Alto and Fortinet syntax. You paste in a list of prefixes and it returns a block you can paste into a change window, which beats hand-typing forty route statements.
How does the uptime monitoring alert me?
By email, on every transition - once when a target goes down and again when it recovers, rather than repeatedly while it is broken. It also warns you before a TLS certificate expires. You can invite colleagues into a shared organisation so alerts are not tied to one person.
Do you store the addresses I type into the subnet calculator?
No. Those tools do their arithmetic in your browser; the values are never sent to a server, so there is nothing on our side to store. The same is true of the timezone and IPv6 tools.
What does the visitor counter on this page record?
A single number in a file, and nothing else. No IP address, no browser details, no timestamp and no per-visitor record. It increments once per browser session and cannot identify anyone.