Imported my old blog

A comment on an ancient post on my old blog reminded me of its existence. I’ve now imported the material from there to my own domain and so historic posts from way-back-when can be read here. The old site will stay online for the time being, to avoid breaking possible links.

DNS, DDNS, and DHCP on a Linux router – Part 2

In a previous post I described how to set up a simple and efficient router and perimeter firewall on just about any computer. What I kind of glossed over was DNS and DHCP. The barebones solution I described will work for automatically connecting new devices to the network and allowing them to reach Internet resources… Continue reading DNS, DDNS, and DHCP on a Linux router – Part 2

Restoring an accidentally migrated mail user to On-Prem Exchange

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

Build your own router with nftables – Part 1

Introduction A few years ago, Jim Salter wrote a number of articles for Ars Technica related to his “homebrew routers“. Much of what he wrote then still stands, but time marches on, and now that I rebuilt my home router, I figured the lessons should be translated to a modern Ubuntu installation and the more… Continue reading Build your own router with nftables – Part 1

Set up TPM support in vCenter on Dell R7515

Quick HowTo/reminder to myself on how to activate TPM on ESXi hosts connected to vCenter. The smoothest way is to configure the servers before they are connected to vCenter: Otherwise they must be removed from the inventory and re-added. The BIOS security settings must be correctly configured: Select System Security. TPM Security must be turned… Continue reading Set up TPM support in vCenter on Dell R7515

Fixing vSAN driver compatibility on Dell R7515

A while back, we purchased some vSAN Ready nodes for a new cluster. The machines came with ESXi installed in an all-NVMe configuration, but when setting up vSAN, Skyline Health kept complaining that the driver used for the write-intensive cache drives wasn’t certified for this purpose. I opened support cases with both VMware and Dell… Continue reading Fixing vSAN driver compatibility on Dell R7515

Email address tags in Postfix and Dovecot

What if you could tag the mail address you provide when registering for various services to simplify the management of the inevitable stream of unsolicited mail that follows? If you could register myname+theservicename@mydomain.tld it would make it very easy to recognize mail from that service – and it would make it easy to pinpoint common… Continue reading Email address tags in Postfix and Dovecot

ZFS backups in Proxmox – Part 2

A while ago I wrote about trying out pve-zsync for backing up some Proxmox VE entities. I kept using regular Proxmox backups for the other machines, though: It is a robust way to get recoverable machine backups but it’s not very elegant. For example all backups are full: There’s no logic for managing incremental or… Continue reading ZFS backups in Proxmox – Part 2