Steps to take to protect an internet-facing Raspberry PI (or other Debian) from brute-force SSH logins from subnets Note: Fail2ban 0.10.2 on 2020/12/22 Install firewall ufw and log analyzer fail2ban:
sudo apt update
sudo apt install ufw fail2ban
(PiOS Buster: the sshd jail is enabled by default via /etc/fail2ban/jail.d/defaults-debian.conf) Copy /etc/fail2ban/jail.conf to /etc/fail2ban/jail.local. This is the config… Read more »
A little time ago, my (admin) user in Windows 10 was so badly damaged, that I had to re-create it. While that was easily done, I found that the NTFS rights on my D: drive were a bit odd: Every folder had inherited an ACL right from D:\ for my… Read more »
What is Zabbix monitoring? Zabbix is an enterprise-class open source distributed monitoring solution. Zabbix is software that monitors numerous parameters of a network and the health and integrity of servers. Zabbix uses a flexible notification mechanism that allows users to configure e-mail based alerts for virtually any event. This allows… Read more »
One of the more useful Windows features for Windows administrators is the Remote Server Administration Tools pack (RSAT). Apart from allowing you to install GUI elements in the Administrative Tools menu, this can also install the command-line tools for querying and managing Active Directory: dsquery.exe, dsadd.exe, dsget.exe, dsmod.exe, dsmove.exe and… Read more »
Today I was viewing the performance statistics in task manager on Server 2012 R2, and noticed that disk performance is not included, in contrary to showing up on my Windows 10 machine’s task manager.
In PowerShell, there is the Get-Process cmdlet. However, this does not return the ParentProcessId property, so it is unsuitable for displaying an indented process tree, which you, for instance, could send by email. Luckily, there is the Get-WMIObject cmdlet that can return the ParentProcessId. How to get a Process Tree… Read more »
Reading the Windows registry from PowerShell can be a bit cumbersome, when all you wanted to retrieve is the value of an item under a key, at least with PowerShell version before v5. The Get-ItemProperty can be used to enumerate the items and their values under a registry key, but… Read more »
I setup a CentOS 7 server recently, that regrettably needs open SSH to the outside world. As I don’t dabble in CentOS that much, I thought I’d write out the instructions for myself and others to install fail2ban. This will block people trying to bruteforce your server with lots of… Read more »
By far the most popular and easy to setup firewall for Ubuntu is UFW, which stands for the ‘Uncomplicated FireWall’. In this tutorial I’ll provide some examples for setups with UFW. I tested the following lines on a fresh Ubuntu 16.04 installation, but this should all work the same with… Read more »
When checking my cloned Ubuntu 14.04 LTS VM, I noticed that it still contained the volume group name from the original, which is of course not desired. It seemed fairly simple, but I kept receiving an error with update-grub, reporting the old Volume Group name:
/usr/sbin/grub-probe: error: failed to get canonical path of `/dev/mapper/<Old VG>-root'.
Steps to be done… Read more »