Experiencing Technology https://blog.tinned-software.net Tinned-Software Blog Wed, 19 Apr 2017 19:10:44 +0000 en-US hourly 1 https://wordpress.org/?v=4.7.4 Update to PHP 5.6 on CentOS 6 using remi repository https://blog.tinned-software.net/update-to-php-5-6-on-centos-6-using-remi-repository/ Mon, 17 Apr 2017 08:00:15 +0000 https://blog.tinned-software.net/?p=2256 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

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Permanently reject a specific email sender address using postfix https://blog.tinned-software.net/permanently-reject-a-specific-email-sender-address-using-postfix/ Mon, 27 Mar 2017 18:26:09 +0000 https://blog.tinned-software.net/?p=2295 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

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Certificate Transparency and unauthorized certificates https://blog.tinned-software.net/certificate-transparency-and-unauthorized-certificates/ Mon, 06 Mar 2017 09:47:09 +0000 https://blog.tinned-software.net/?p=2379 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

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How to get scrollbar arrows in Linux Mint 17 https://blog.tinned-software.net/how-to-get-scrollbar-arrows-in-linux-mint-17/ Mon, 13 Feb 2017 09:11:12 +0000 https://blog.tinned-software.net/?p=2325 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

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Verifying SSH configuration with a scan https://blog.tinned-software.net/verifying-ssh-configuration-with-a-scan/ Mon, 23 Jan 2017 10:20:04 +0000 https://blog.tinned-software.net/?p=2281 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

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Debug SSH Connection issue in key exchange https://blog.tinned-software.net/debug-ssh-connection-issue-in-key-exchange/ Mon, 02 Jan 2017 09:41:21 +0000 https://blog.tinned-software.net/?p=2284 Securing a server means hardening the SSH server settings, but doing so can also cause issues with ssh clients. Finding the cipher or algorithm causing a failled connection can be tricky. Depending on the client used, the error message might be very … Continue reading

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Automount a luks encrypted volume on system start https://blog.tinned-software.net/automount-a-luks-encrypted-volume-on-system-start/ Mon, 12 Dec 2016 07:21:58 +0000 https://blog.tinned-software.net/?p=2273 Linux supports encrypted volumes with luks. When a luks encrypted volume is set up during installation to be booted from, the volume is already configured and set up. When an encrypted volume is set up afterwards, the volume remains locked until … Continue reading

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Review: The perfect duo – powerbank and solar charger https://blog.tinned-software.net/review-the-perfect-duo-powerbank-and-solar-charger/ Mon, 21 Nov 2016 07:23:25 +0000 https://blog.tinned-software.net/?p=2352 Do you live in a sunny country? Want to use the sun’s energy to charge your mobile devices? This duo of a solar charger and a USB powerbank will let you harvest the sun and charge your devices whenever you … Continue reading

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Harden SSH server settings https://blog.tinned-software.net/harden-ssh-server-settings/ Mon, 31 Oct 2016 08:17:09 +0000 https://blog.tinned-software.net/?p=2279 Many Linux Administrators use ssh on a daily basis. Many of the ssh servers are in their default configuration. Not changing the default configuration puts the security of the server at risk. That is why it is important to follow a few … Continue reading

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Manage photo EXIF data via terminal https://blog.tinned-software.net/manage-photo-exif-data-via-terminal/ Mon, 10 Oct 2016 06:27:16 +0000 https://blog.tinned-software.net/?p=2267 Additional to the GUI tools that are available to manage EXIF information in photos, there are also command line tools that can do this as well. Command line utilities allow you to script the processing of photos. The following shows … Continue reading

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Get vim to paste content without modification https://blog.tinned-software.net/get-vim-paste-content-without-modification/ Mon, 19 Sep 2016 07:38:55 +0000 https://blog.tinned-software.net/?p=2166 When content is pasted into vim, it tries to automatically detect and re-indent the content. This works most of the time but sometimes it does not, and that can be annoying, but vim would not be so popular if there wasn’t … Continue reading

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Change Date and Time format for LinuxMint panel applet https://blog.tinned-software.net/change-date-and-time-format-for-linuxmint-panel-applet/ Mon, 29 Aug 2016 07:53:44 +0000 https://blog.tinned-software.net/?p=2185 Modern Linux distributions like LinuxMint provide a nice GUI which is highly configurable. There are so many options and possibilities that most users new to it cannot find where things are configured. Finding the right options means taking some time to … Continue reading

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Manage SSH-keys with the SSH-agent https://blog.tinned-software.net/manage-ssh-keys-with-the-ssh-agent/ Mon, 08 Aug 2016 09:01:33 +0000 https://blog.tinned-software.net/?p=2176 Many webservices generate ssh keys to access their service. With the amount of services the number of SSH keys grows. To avoid dealing with the keys in the command line and the ssh_config(5), you can simply add the ssh-key to the … Continue reading

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Create a luks encrypted partition on Linux Mint https://blog.tinned-software.net/create-a-luks-encrypted-partition-on-linux-mint/ Mon, 18 Jul 2016 08:03:19 +0000 https://blog.tinned-software.net/?p=2203 Encryption is not only for someone who has something to hide. There are simple concerns like a lost or stolen laptop that justify a full disk encryption. There are only a few steps necessary to create a encrypted partition. In … Continue reading

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Dimension rrdtool databases with years worth of values https://blog.tinned-software.net/dimension-rrdtool-databases-with-years-worth-of-values/ Mon, 27 Jun 2016 08:41:19 +0000 https://blog.tinned-software.net/?p=2195 To create an rrd datbase file needs a certain amount of understanding of what you monitor, and for how long the data needs to be kept, and of course, storage space is also a consideration when creating a new rrd … Continue reading

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Configuring vim for dark terminal windows https://blog.tinned-software.net/configuring-vim-for-dark-terminal-windows/ Mon, 06 Jun 2016 09:03:53 +0000 http://blog.tinned-software.net/?p=2143 On CentOS, vim is installed with a default configuration. These defaults might be right for some users but not for everyone. I will describe the two settings I personally find most annoying for my setup. One of the assumtions in the … Continue reading

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Recompress git repository https://blog.tinned-software.net/recompress-git-repository/ Mon, 16 May 2016 08:13:45 +0000 http://blog.tinned-software.net/?p=2076 Git repositories are getting bigger and bigger. To reduce the disk space used by a repository, git provides some housekeeping functionality. Compared to other version control systems, git stores the complete history in each cloned repository if not told otherwise. This can … Continue reading

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Modify file and directory date https://blog.tinned-software.net/modify-file-and-directory-date/ Sat, 23 Apr 2016 21:13:33 +0000 http://blog.tinned-software.net/?p=2138 Sometimes it is necessary to change a file or even a directory’s timestamp. This sounds easy, but most GUI utilities installed out of the box on OS X as well as on Linux don’t let you change a file’s timestamp. … Continue reading

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Shrink sparse cqow2 disc image https://blog.tinned-software.net/shrink-sparse-cqow2-disc-image/ Wed, 30 Mar 2016 18:50:24 +0000 http://blog.tinned-software.net/?p=2071 There might be cases when a VM temporarily used a lot of disk space which is then not needed any more. The sparse disk image format qcow2 will grow as the disk space is used, but it does not automatically shrink. … Continue reading

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Perform a portscan using netcat https://blog.tinned-software.net/perform-a-portscan-using-netcat/ Mon, 14 Mar 2016 22:10:57 +0000 http://blog.tinned-software.net/?p=2119 To perform a port scan, most of the time we think about a separate program. Sometimes it is not necessary to look that far. On most Linux systems netcat is already installed or can be installed easily from a repository. Continue reading

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Restrict SSH access to port forwarding to one specific port https://blog.tinned-software.net/restrict-ssh-access-to-port-forwarding-to-one-specific-port/ Tue, 01 Mar 2016 18:49:19 +0000 http://blog.tinned-software.net/?p=2083 Allowing access to an unprotected service on a server is always a problem. Sometimes the easiest way is to not expose this service to the network but allow access via ssh port-forwarding, but how to limit the SSH account to … Continue reading

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Generate public SSH key from private SSH key https://blog.tinned-software.net/generate-public-ssh-key-from-private-ssh-key/ Mon, 15 Feb 2016 18:32:20 +0000 http://blog.tinned-software.net/?p=1987 A lost SSH public-key or a web service generates an SSH key but does not provide the public-key part to you. What to do now? There is a solution for this situation. Continue reading

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Review: iPhone 6 Battery Charger Case https://blog.tinned-software.net/review-iphone-6-battery-charger-case/ Mon, 01 Feb 2016 18:32:55 +0000 http://blog.tinned-software.net/?p=2088 In today’s world the smartphone has become the mobile communication center in our pocket. All the wireless technologies around us communicate with our smartphones. Wireless technologies drain the battery, but there is a way to extend the battery life. When using … Continue reading

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Managing shell commands and processes https://blog.tinned-software.net/managing-shell-commands-and-processes/ Mon, 18 Jan 2016 16:32:17 +0000 http://blog.tinned-software.net/?p=1828 Not every command you might execute only runs for a couple of seconds. When you have a long running command a couple of problems can come with it. When the ssh connection is not stable, the command might be interrupted, … Continue reading

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Setup gitolite to manage git repositories https://blog.tinned-software.net/setup-gitolite-to-manage-git-repositories/ Mon, 04 Jan 2016 17:56:30 +0000 http://blog.tinned-software.net/?p=2018 Git provides all the required tools to create remote repositories. As explained in Setup gitosis to manage git repositories, a bare repository can be generated and managed manually or with gitosis, but this is not the only git repository management … Continue reading

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Utility df shows inconsistent calculation for ext filesystems https://blog.tinned-software.net/utility-df-shows-inconsistent-calculation-for-ext-filesystems/ Mon, 21 Dec 2015 19:39:33 +0000 http://blog.tinned-software.net/?p=1970 The output of “df” might sometimes seem inconsistent or wrong and especially in some situations the presented information seems to obviously not match up. The fact is, the information is not wrong but the calculation behind it considers facts that … Continue reading

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Replace section in file with content from another file https://blog.tinned-software.net/replace-section-in-file-with-content-from-another-file/ Mon, 07 Dec 2015 18:50:35 +0000 http://blog.tinned-software.net/?p=1774 While automating things, you might come across the need to replace a block of lines within a file – like replacing a section with IP addresses you want to block in an .htaccess file. Automating this task means replacing this bunch of … Continue reading

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Gitosis Arguments to command look dangerous https://blog.tinned-software.net/gitosis-arguments-to-command-look-dangerous/ Mon, 23 Nov 2015 17:54:14 +0000 http://blog.tinned-software.net/?p=2014 Dealing with non-English languages, you might come across a couple of issues caused by special characters. Even gitosis has its limitations in this area. One of the error messages caused by special characters is: “Arguments to command look dangerous”. When a … Continue reading

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Resize Proxmox VM disc via command line without LiveCD https://blog.tinned-software.net/resize-proxmox-vm-disc-via-command-line-without-livecd/ Mon, 09 Nov 2015 16:56:14 +0000 http://blog.tinned-software.net/?p=1963 To increase the disc size from the command line, login to the Proxmox host. In the command line you can list the VMs configured by this command to find the VMID needed. For this example the VM with the VMID … Continue reading

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Monit restart not working on CentOS – no pid-file after restart https://blog.tinned-software.net/monit-restart-not-working-on-centos-no-pid-file-after-restart/ Mon, 26 Oct 2015 18:02:08 +0000 http://blog.tinned-software.net/?p=1990 Monit is a monitoring tool that can monitor processes, files and more. In the event of a failed monitor, monit is able to alert or trigger an action. Often the action triggered is to restart the monitored daemon. With the … Continue reading

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