Author: halfgaar

http://www.halfgaar.net/

Halfgaar is Wiebe. Wiebe is a contributing author on this weblog. He also has a lot of stuff (such as long, in-depth articles) on his personal website.

Wiebe works at YTEC, where he is a senior developer of customer-specific tailor-made software (“klantspecifieke maatwerk software“) for clients in a few select markets: wholesale, printing and healthcare.

Sending mail from a NATed host with Postfix

When sending mail from a host behind NAT, you will run into trouble when the "From" says "root@host.localdomain", because receiving servers will refuse that domain. Read More »
By halfgaar, 3 years ago, on June 03, 2016, at 11:06 | Comments closed

Download dmcrypt (cryptsetup) encryption key from remote server and auto mount

One of the inconveniences of encryption is the need to open the encrypted volume by hand when the computer/server boots. Luckily, you can easily automate that securely. You need a machine that will act as a key server, whether that's a Raspberry Pi or some VPS you hire. Read More »
By halfgaar, 3 years ago, on May 22, 2016, at 20:05 | Comments closed

Preventing degraded array on every boot

I had a server that booted with a degraded array every time, because there was a USB drive attached to it, that messed up the auto detection. I solved it by putting this in mdadm.conf: Read More »
By halfgaar, 3 years ago, on April 27, 2016, at 09:04 | 1 comment

Decreasing shutdown time of MySQL with large transaction log file

If you need/have a large transaction log file, a shut down can take a while. This post lists how you can force a flush before you do so, decreasing shut down time. Read More »
By halfgaar, 5 years ago, on July 15, 2014, at 17:07 | 1 comment

Excellent article about LC resonance resulting from turn-on transients

This article gives a good explation of LC resonances caused by turn-on transients. Read More »
By halfgaar, 5 years ago, on April 26, 2014, at 17:04 | Comments closed

Better nagios SMS and E-mail messages

Just for my references. I made changes to it before, but I now added the comments to them (for custom notifications and acknowledgements): Read More »
By halfgaar, 5 years ago, on April 04, 2014, at 16:04 | Comments closed

Teamviewer replacements

ChunkVNC consists of three parts, InstantSupport, Repeater and Viewer. Read More »
By halfgaar, 5 years ago, on March 11, 2014, at 12:03 | Comments closed

Iptables: limiting amount of connections per IP

Short and improved version of this. Read More »
By halfgaar, 5 years ago, on February 04, 2014, at 11:02 | Comments closed

Dumping MySQL users and grants

MySQL stores its users and grants in a very annoying, non-clonable format. I found this post, describing how you can extra them. Read More »
By halfgaar, 5 years ago, on January 17, 2014, at 13:01 | Comments closed

Openswan random failures

I have an annoying problem with my Openswan VPN server. When I connect from a Windows XP machine, from that point on, I can only connect with that machine (or perhaps other Windows XP machines as well). On the other hand, when I connect with a Windows 7 machine first, connecting from Windows XP is no longer possible. Read More »
By halfgaar, 5 years ago, on December 01, 2013, at 19:12 | Comments closed