Notes on security leadership, infrastructure and architecture
Proxmox VE is free, built on Debian, and covers clustering, high availability, Ceph storage and backups through one web interface. Why I recommend it over VMware and Hyper-V for small deployments, and where it falls short.
Exchange Management Shell one-liners that count the active user mailboxes, shared mailboxes and distribution groups in an Exchange 2016 organisation.
Create a key and a SAN certificate request with OpenSSL, have it signed by your CA, and install the certificate in the Proxmox VE web interface.
Exchange limits ActiveSync to about 10 MB by default, so large attachments fail to open on mobile devices. Two values in the Sync web.config raise the limit.
Before RouterOS had a proper command, seeing what you advertise to a BGP peer meant saving the sent attributes and reading them from a pcap. Kept for reference.
One PowerShell line shows which Remote Desktop license server an RD Session Host is configured to use.
Set your own background image and colour on a Microsoft Teams Rooms device with a SkypeSettings.xml file, and the image size it expects for one or two screens.
Use a FIDO2 security key such as a YubiKey 5 to sign in to an Azure AD joined Windows 10 device: the requirements, the Azure AD setting and the Intune profile.
"VTP VLAN configuration not allowed when device is in CLIENT mode" means VLANs are managed elsewhere. One show command tells you which switch is the VTP primary.
Outlook 2016 shows a blank sign-in window and keeps asking for a password in a hybrid Exchange setup with Modern Authentication. The cause can be a missing autodiscover service principal name.
