Create hardware raid on HP via hpacucli

Posted on 2017-08-21 by Gerhard

Configuring a new hardware raid on a HP server can be done comfortably from the Linux command line without restarting the server. HP provides a small command line tool for this job. The following shows how this tool can be … Continue reading →

Posted in Linux Administration | Tagged , , , , , | Comments Off on Create hardware raid on HP via hpacucli

Linux Mint – Mount an NFS share automatically

Posted on 2017-07-31 by Gerhard

Linux Mint comes pre-installed with all components to mount Windows File sharing (SMB/CIFS) but does not support NFS out of the box. The following post will explain how to enable Linux Mint to mount a NFS share. Additionally the NFS … Continue reading →

Posted in Linux Administration | Tagged , , , | Comments Off on Linux Mint – Mount an NFS share automatically

Create GnuPG key with sub-keys to sign, encrypt, authenticate

Posted on 2017-07-10 by Gerhard

In order to use a GnuPG key on a smartcard or Yubikey, a GnuPG key needs to be created. This post will show you how to create a GnuPG key with sub-keys for signing, encryption and authentication. The authentication key can … Continue reading →

Posted in Encryption, Security | Tagged , , , , , , | Comments Off on Create GnuPG key with sub-keys to sign, encrypt, authenticate

apt – install the package that contains a specific file

Posted on 2017-06-19 by Gerhard

Sometimes a command that you execute complains about a dependency being missing on the system. From the file name in the error message it is often not possible to know exactly which package needs to be installed to resolve the … Continue reading →

Posted in Linux Administration, Security | Tagged , , , , , , , | Comments Off on apt – install the package that contains a specific file

Understand the basics of rrdtool to create a simple graph

Posted on 2017-05-30 by Gerhard

rrdtool is a powerful tool to store time series data and create graphs. It is very easy to create your first simple graph. This how-to will show the quickest way to generating your first graphs while explaining the options used. rrdtool is used in … Continue reading →

Posted in Monitoring | Tagged , , | Comments Off on Understand the basics of rrdtool to create a simple graph

Increase the size of a LUKS encrypted partition

Posted on 2017-05-08 by Gerhard

Even encrypted discs or partitions sometimes need to have their size increased. A LUKS encrypted volume consists of different layers which all need to be resized. To resize an encrypted volume, multiple steps have to be performed to use the additional … Continue reading →

Posted in Encryption, Linux Administration, Security | Tagged , , , , , | Comments Off on Increase the size of a LUKS encrypted partition

Update to PHP 5.6 on CentOS 6 using remi repository

Posted on 2017-04-17 by Gerhard

With CentOS being a conservative distribution, security patches are still applied to CentOS 6, but no new versions are available. When running some websites – like Virtualmin – on CentOS 6, the old PHP version 5.3.3 can cause problems. Updating to a newer … Continue reading →

Posted in PHP, Web technologies | Tagged , , | Comments Off on Update to PHP 5.6 on CentOS 6 using remi repository

Permanently reject a specific email sender address using postfix

Posted on 2017-03-27 by Gerhard

Postfix generally accepts all sender addresses. It might be needed in some rare cases to reject one sender addresses for some reason. With postfix, there is the possibility to use the “check_sender_access” to set individual actions per sender address. For the … Continue reading →

Posted in Linux Administration, Mailserver | Tagged , , , , , , | Comments Off on Permanently reject a specific email sender address using postfix

Certificate Transparency and unauthorized certificates

Posted on 2017-03-06 by Gerhard

I own a domain which was bought a few months back which is managed by CloudFlare’s service in DNS-only mode. As I intended to only use CloudFlare’s DNS service, I disabled every option except the DNS related features. You can imagin the surprise to see certificates issued for my domain without my knowledge. Continue reading →

Posted in Security, Web technologies | Tagged , , , , , | 1 Comment

How to get scrollbar arrows in Linux Mint 17

Posted on 2017-02-13 by Gerhard

Linux Mint is missing the scrollbar arrow buttons at the end of the scrollbars. There are situations in which those buttons can be very useful. This how-to will explain how to get them back. Sadly I could not find any … Continue reading →

Posted in Linux Administration | Tagged , , , , , | Comments Off on How to get scrollbar arrows in Linux Mint 17