We recently migrated most of our users to Office 365, and due to a miscommunication, three users that should have stayed on premises were migrated, converted to the RecipientTypeDetails RemoteUserMailbox, and had their local mailboxes disconnected. Reconnecting their mailboxes failed as they were of the wrong user type: The solution was to remove the Exchange… Continue reading Restoring an accidentally migrated mail user to On-Prem Exchange
Category: Windows
Fixing “No DKIM keys saved for this domain” in EOP and Office365
Sometimes a newly added domain in Microsoft EOP will not let you enable DKIM from the web user interface. The only workaround I know of is to prepare the domain using PowerShell. To connect a PS session to O365, I use the following script, ripped straight from Microsoft’s documentation: After waiting for an eternity for… Continue reading Fixing “No DKIM keys saved for this domain” in EOP and Office365
DNS/DHCP issues in modern Windows versions
Static IP addresses are a solid way to configure machines if you have few enough of them to manage them manually. But the more ability you want to have to change things on the fly, the more limiting such a configuration scheme becomes. Unfortunately I’ve had severe problems with getting servers with DHCP leases (or… Continue reading DNS/DHCP issues in modern Windows versions
FTP server on IIS
I recently had cause to set up an FTP server for internal use on a Windows server, and I bumped into an issue that took me a little while to figure out, since I had never done it before: I wanted to give a domain user account an isolated directory, and started out by creating… Continue reading FTP server on IIS
Default behavior should not be stupid
I ran into a problem that truly surprised me yesterday: One of our remote desktop users accidentally deleted an entire folder of customer data. He was seriously angry, and rightfully so: He had pressed the Delete key on the keyboard at the wrong moment, after which the folder and its entire substructure was removed from… Continue reading Default behavior should not be stupid
Exchange – another lesson learned
This is why we test things before going live: After migrating a test box from the old Exchange environment, it could receive mail just fine, and sending mail out of the organization worked flawlessly too. Unfortunately any mail sent from this account to recipients within the old Exchange environment got stuck in the mail queue.… Continue reading Exchange – another lesson learned
Load Balancing Exchange 2016 behind HAProxy
I recently started the upgrade to Exchange 2016 at work. A huge benefit over Exchange 2010, is that REST based client connections are truly stateless. In effect this means that if a server goes down, clients shouldn’t really notice any issues as long as something redirects them to a working server. In my system, this… Continue reading Load Balancing Exchange 2016 behind HAProxy
The paravirtual SCSI controller and the blue screen of death
For driver reasons, the default disk controller in VMware guests is an emulated LSI card. However, once you install VMware Tools in Windows (and immediately after installing the OS in most modern Linux distributions), it’s possible to slightly lower the overhead for disk operations by switching to the paravirtual SCSI controller (“pvscsi”). I’m all for lower… Continue reading The paravirtual SCSI controller and the blue screen of death
Fixing (some) access errors in Veeam
I just spent a couple of hours troubleshooting a stupid problem where I got access errors when trying to backup a VM from a newly-installed Veeam server. Searching forums for answers I got red herrings all over the place, from opening up the Windows Firewall for RPC traffic, to removing Veeam VSS files from various… Continue reading Fixing (some) access errors in Veeam
OpenVPN 2.x and Windows Firewall
The documentation for OpenVPN is pretty good, but I found a detail that may cause some confusion in a Windows environment, so I thought I’d address it here: What do you do if you need to run OpenVPN but still want the Windows Firewall to work on your Windows server? The background for this issue is how Windows decides what… Continue reading OpenVPN 2.x and Windows Firewall