I’m using Let’s Encrypt certificates for a while now. In the past, I used the standalone plugin (TLS-SNI-01) to get or renew my certificates. But now I switched to the DNS plugin. I run my own name servers with BIND, so it was a very low hanging fruit to get this plugin to work.
To get or renew a certificate, you need to provide some kind of proof that you are requesting the certificate for a domain that is under your control. No certificate authority (CA) wants to be the CA, that hands you out a certificate for google.com or amazon.com…
The DNS-01 challenge uses TXT records in order to validate your ownership over a certain domain.… Read more
A customer is running their PCs behind their VoIP phones. Nothing unusual, most VoIP phones I know have an embedded ethernet switch, so that you only need one cable to connect PC and VoIP phone to your network.
As part of a network security project, my colleague and I implemented IEEE 802.1X port-based Network access control at one of our customers networks. The setup consists of multiple Alcatel-Lucent Enterprise OmniSwitches (6450-P10 and 6860/E) and Aruba ClearPass.
We noticed, that mac-address based authentication worked all the time, but 802.1x fails constantly if the client was connected to a VoIP phone (NEC DT700).… Read more
I hope that you are not reading this blog post while searching for a solution for a failed cluster. If so, feel free to leave a comment if this blog post saved your evening or weekend. :)
Last friday, a change at one of my customers went horribly wrong. I was not onsite, but they contacted me during the night from friday to saturday, because their most important Windows Server Failover Cluster was unable to start after extending a shared VMDK.
They tried something pretty simple: Extending an virtual disk of a VM. That is something most of us doing pretty often. The customer did this also pretty often. It was a well known task… Except the fact, that the VM was part of a Windows Server Failover Cluster.… Read more
Michael White published the third release of his “What is in the bag” blog post. In reference to this, I would like to share the content of my bag.
I used a RIMOWA Salsa business trolley for several years. Unfortunately, it broke in June 2017 and a repair was refused by RIMOWA. I was very disappointed of the product quality and the customer service experience with RIMOWA.
I decided to switch to a backpack, which felt much more comfortable than carrying or pulling the RIMOWA trolley.
This is only a short blog post to document a solution for a very annoying problem. After the automatic update of my Outlook to the latest Office 365 build (version 1809), it has started to prompting for credentials. I’m using Outlook to access a Microsoft Exchange 2016 server (on-premises), without any hybrid configuration. A pretty simple and plain Exchange 2016 on-prem deployment.
I knew, that it has to be related to Office 365, because the Outlook 2016 on my PC at the office was not affected. Only the two Office 365 deployments on my ThinkPad T480s and ThinkPad X250.
To make this long story short: ExcludeExplicitO365Endpoint is the key!… Read more
It is common that vendors offer their products in special editions for SMB customers. VMware offers VMware vSphere Essentials and Essentials Plus, Veeam offers Veeam Backup Essentials, and now Vembu has published Vembu BDR Essentials.
Backup is important. There is no reason to have no backup. According to an infographic published by Clutch Research at the World Backup Day 2017, 60% of all SMBs that lost all their data will shutdown within 6 months after the data loss. Pretty bad, isn’t it?
When I talk to SMB customers, most of them complain about the costs of backups. You need software, you need the hardware, and depending on the type of used hardware, you need media.… Read more
I have worked with a lot of backup software products during my career, but for the last years I have primarily worked with MicroFocus Data Protector (former HP OmniBack, HP Data Protector, or HPE Data Protector), and Veeam Backup & Replication. Data Protector was a great solution for traditional server environments, or when UNIX (HP-UX, AIX, Solaris etc.) compatibility was required. Features like Zero Downtime Backups, LAN-free or Direct SAN backups were available for many years. But their code quality has suffered severely in the recent years. The product no longer seemed like a one-stop shop.… Read more
When taking a backup with Veeam Backup & Replication, a VM snapshot is created to get a consistent state of the VM. The snapshot is taken prior the backup, and it is removed after the successful backup of the VM. The snapshot grows during its lifetime, and you should keep in mind, that you need some free space in the datastore for snapshots. This can be a problem, especially in case of multiple VM backups at a time, and if the VMs share the same datastore.
Benefit of storage snapshots
If your underlying storage supports the creation of storage snapshots, Veeam offers an additional way to create a consistent state of the VMs.… Read more
In January 2017, I wrote an article about how to protect your WordPress blog using the WP Fail2Ban plugin, fail2ban on your Linux/ FreeBSD host, and CloudFlare. Back then, the fail2ban was using the CloudFlare API V1, which was already deprecated since November 2016.
Although the actions were updated later to use CloudFlare API V4, I still had problems with the unbaning of IP addresses. IP addresses were banned, but the unban action failed.
This is the unban action, which is included in fail2ban (taken from fail2ban-0.10.3.1 which is shipped with FreeBSD 11.1-RELEASE-p10):