Infrastructure

TL;DR If Windows 11 24H2 (and 25H2) machines are randomly locking out AD accounts, and AD swears the lockout is coming from the machine while the machine swears nothing failed to log in. It’s Credential Manager quietly throwing your cached Exchange mailbox password at your domain controller. No official Microsoft fix exists as of this writing. Skip to Fixes if you just want it stopped. Symptoms Random lockouts of user AD accounts, only on Windows 11 24H2 and newer. AD shows the lockout coming from the user’s machine. The machine itself shows no failed logins, but Credential Manager logs authentication failures. The issue survives clearing Credential Manager, wiping and reinstalling Windows, and follows the user to literally any other machine they log into as long as that machine is also 24H2+. Roll a user back to Windows 10 or 23H2 and it disappears immediately. Cause Starting in 24H2, Microsoft leaned harder into cross service SSO, and Credential Manager got more aggressive about it: it now assumes your Exchange/email login, your M365 login, and your local AD login are all the same account, and starts trying cached credentials against whatever it can reach. ...

Here is my recommendation for quickly learning at least the basics of infrastructure: Hardware If you can start with a cluster of at least 3 computers. If not a single computer for a hypervisor will work If not then VirtualBox or VMWorkstation will get you started with the absolute basics until you can get a hypervisor If you have a couple old computers or laptops (at least 8gb ram each) then start with those. I recommend grabbing a few sff Dell or sff Lenovo or Intel nucs from eBay. If you can put a 1tb nvme in each one and as much RAM as possible. If you want to learn Phones get a cheap VOIP phone that will work with Asterisk (I will explain this later). If you are interested in Enterprise equipment pick up a few old Servers and a Server Rack (this WILL be expensive) Use Labgopher to find good deals on used servers https://www.labgopher.com/ If you want to focus on networking grab a used Firewall (Fortigate is one of the cheapest, Palo Alto is really fucking good, Sophos is pretty cheap, but I personally would avoid Cisco Firewalls) and a fancy Layer 3 Switch (Cisco, Juniper, Netgear, Ubiquiti are all popular brands) Also don’t forget to get a USB to rj45 serial cable for managing the switches and firewalls Connect them all to your Lab network and install your hypervisor of choice onto all of them. If you can get 4 computers I would make one of them a dedicated NAS with something like TrueNAS or Unraid. The benefit of a NAS is that you can store your VMs on it and because it is on the nas shared by all nodes in the cluster you can do things like instant migration between hypervisor nodes. I’m not sure how important that is to learn or play around with, but it is super cool to see VMs pop between nodes in an instant. It also allows you to use High Availability (HA). ...