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
Linux Mint – Mount an NFS share automatically
Posted in Linux Administration
Tagged autofs, LinuxMint, mount, NFS
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Create GnuPG key with sub-keys to sign, encrypt, authenticate
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 authentication, encryption, gnupg, gpg, pgp, signing, subkeys
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apt – install the package that contains a specific file
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 apt, apt-file, Debian, gnupg, hopenpgp-tools, Linux, LinuxMint, ubuntu
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Understand the basics of rrdtool to create a simple graph
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 create, graph, rrdtool
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Increase the size of a LUKS encrypted partition
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 cryptsetup, encryption, luks, parted, partitioning, resize
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Update to PHP 5.6 on CentOS 6 using remi repository
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 CentOS, PHP, yum
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Permanently reject a specific email sender address using postfix
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 check_sender_access, email, postfix, recipient_restrictions, reject, sender address, sender_access
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Certificate Transparency and unauthorized certificates
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 certificate, Certificate Transparency, Cloudflare, Comodo, CT, DNS
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Verifying SSH configuration with a scan
Managing a number of Linux servers and keeping them secure can be a challenge. Certain tools can make the life of an admin a lot easier. To ensure an ssh daemon complies with a desired security configuration the admin can use a scanner … Continue reading
