Sysinfo.io

April 23, 2019 7:45 pm By Travis Leave a Comment

Change Grub Default Boot Entry on Linux Mint

I'm dual booting Windows and Linux Mint on my laptop. The grub default is to boot into Linux Mint, however many people will probably want to either boot the last boot entry saved, or boot into Windows instead. My preference is for grub to select by default and boot into whatever boot entry was selected last. This makes it easy if I want to just hit reboot and know that I'm going to load into the last used operating system. Boot into last booted Operating System: You will need to change/add the following two lines in the grub config: /etc/default/grub.cfg […]

April 21, 2019 8:14 am By Travis Leave a Comment

How to Reset Secure Channel On Active Directory Domain Controller

When you're a little too careless about virtualizing your domain controllers, cloning, migrating, backing up and restoring, returning from vacation and deciding that having a single box holding all the FSMO roles is dangerous to the network, you will inevitably find yourself in the same situation I've found myself in. A tell-tale sign that you need to manually reset the KDC secure channel on your problematic domain controller can be diagnosed with the following symptoms: Any mechanism that relies on Kerberos authentication tickets will fail Practically all subsystem services and listening endpoints will cease to function (non KDC-related services like […]

April 20, 2019 10:14 am By Travis Leave a Comment

Run Systemd Script Before System Shutdown

For the sheer hell of it, a few weeks ago I wanted to see if I could properly and successfully retain the NGINX cache of sysinfo.io and have it persist across system reboots. In order to achieve this goal, I needed to create a shell script, define a new Systemd service unit, and find a way to run the Systemd script before system shutdown (reboots are included via "Before=" declaration). This website is configured to store the NGINX cache in its tmpfs file system, which is a special Linux in-memory file system that exposes and abstracts itself typically to a […]

April 20, 2019 7:55 am By Travis Leave a Comment

Learn Systemctl Usage to Manage Systemd Service in Linux

Systemd is new service manager for Linux. It's a replacement for all previous init systems (SysV/SysVinit & Ubuntu's Upstart) and can manage system startup and services. It starts up and supervises the entire system. In the article we are using centos 7.0 installed with systemd 216 version and the latest version is available for download from freedesktop.org. Since 2015, the majority of Linux distributions have adopted systemd and it is considered a de facto standard. The name systemd adheres to the Unix convention of naming daemons by appending the letter d. It also plays on the term "System D", which refers to […]

April 20, 2019 5:54 am By Travis Leave a Comment

Force Delete Windows Server DHCP Failover Relationship

If you've found yourself here then chances are you messed up one of your domain controllers or at least one of your DHCP Servers. I admit I did. More than once. And I'm tired of querying for the elusive "Remove-DhcpServerv4Failover" PowerShell script to force delete the Windows Server DHCP failover relationship. The way content makes its way onto this site is usually split into two categories: Repetition, and one time specialized content not found on the internet (at least difficult). Pick the server you want to keep. Look at your DHCP leases and determine which might be the most […]

April 7, 2019 11:00 am By Travis Leave a Comment

Determine Your Upstream DNS Resolver

The following one-liner Bash will output your upstream DNS resolver. You will need to install the whois package for this to work. Akamai is deprecating whoami.akamai.net and succeeding it with whoami.ds.akahelp.net so if you have a choice of what to count on in the future, I'd go with those. whois $(dig whoami.akamai.net +short) | grep -i 'organization:' DNS=$(dig whoami.ds.akahelp.net +short TXT | awk '{print $2}');whois $(sed -e 's/^"//' -e 's/"$//' <<<"$DNS") | grep -i 'organization' DNS=$(dig whoami.ds.akahelp.net +short TXT | awk '{print $2}');whois $( echo $DNS|tr -d '"' ) | grep -i 'organization' And here is my output: sysinfoio:~$ DNS=$(dig […]