Category Archives: Linux

Problems with Ubuntu 24.04 in VirtualBox 7.0.20 VM on a Windows 10 host

Linux,

I recently had the bright idea to upgrade to Ubuntu 24.04 inside my Ubuntu VM that is running with VirtualBox 7.0.20 on Windows 10.

As you propably guessed: Its a catastrophy.

Not only is there problems with the vmwgfx driver that comes with newer kernels but also Xorg fallback mode is not working anymore. There was regular stack traces at boot that could be to some part fixed by enabling hpet mode.

It also shows regular boot delays or fully gets stuck related to systemd-resolved, oomd or timesyncd.

At this point I would like to show you possibilities to prevent these problems, but I got no advice more than the things mentioned above and disabling 3D acceleration in the settings + using the VMSVGA graphics mode.

I have also tried the VirtualBox 7.1 Beta 1, with no improvements.

Running Dell C1660w/Xerox Phaser 6000B on Ubuntu 24.04

Linux, , , ,

No matter if you are a Windows-, Linux- or Mac-Person, the way some producers of peripheral devices such as printers, plotters, scanners, sensors, diagnostics tools handle their software support, frankly, sucks.

I want to try to supply you with some instructions on how to get a Dell C1660w, a Dell branded version of the Xerox Phaser 6000B, running on your latest Linux distro with a 100% satisfaction guarantee1.

Continue reading Running Dell C1660w/Xerox Phaser 6000B on Ubuntu 24.04 →

Fun with regex: We match the requirements for the HTTPS DNS record type defined by RFC 9460

Linux, PHP, , ,

To be able to fully read, understand and transfer RFCs into a standard-aligned application can be very difficult. You may become a lawyer as well.

We start off with section 2.1 of RFC 9460 which defines the following rules for us to apply:

  • the record data must be formatted as “SvcPriority TargetName SvcParams” where
    • SvcPriority is a number between 0 and 65535
    • TargetName is a domain-name, which is a combination of texts (labels) that can contain alphabetic characters, digits and hyphens, these labels can be up to 63 characters each and can be bonded together using dots up to a length of 255 characters
      • Note: The domain-name is not specified in RFC 9460, but already in RFC 1035
    • SvcParam is one or more of either only a key such as ‘mykey’ or a key-value pair such as ‘mykey=”myvalue”‘ where the quotation mark is mandatory
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Compile SquirrelMail imapproxy with OpenSSL 1.1.1 and 3.0

Linux,

imapproxy is a application aware (POP3/IMAP) proxy, which enables webmailers such as SquirrelMail or Roundcube to save on roundtrips by using a local low-latency connection to a mail server over a high-latency connection that is being kept open.

SquirrelMail as well as imapproxy is very outdated software and you may not want to use it. However, if you really want, you may want to compile it yourself as shown in the rest of this article.

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Dovecot “get_public_key(INBOX) failed: […] Mailbox attributes not enabled”

Linux, OSS, ,

If you use Dovecot as a IMAP or POP3 server, and you have looked around how to secure and design your setup, you propably came across the mail-crypt plugin for Dovecot. The plugin enables you to store mails in an encrypted manner, basically to do so called “encryption at rest”.

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Various approaches to extract the cluster state from keepalived VRRP-instances

Linux, , ,

keepalived can be used to switch one or more IPs between one or more server systems. Typically, the underlying protocol for this is VRRP (Virtual Router Redundancy Protocol).

To determine whether localhost is currently in an active (ACTIVE), passive (BACKUP), or dysfunctional (FAULT) state within the server cluster, there are multiple approaches, each with its own pros and cons.

The goal is to provide a brief overview and examine some methods in detail, making it easier for other system administrators facing the same task.

TLDR: See “Part 5 – DBus”

Continue reading Various approaches to extract the cluster state from keepalived VRRP-instances →