Using a JDK as the runtime image is simply a waste of resources, but it makes it a bit more difficult to get memory- and thread dumps out of the JVM at runtime. Jattach to the rescue. Let’s imagine a situation where we have an image running your Java application using the JRE and you More…
Linux
Installing Lets Encrypt’s SSL certificate to mail server with Postfix and Dovecot
Hi! I’ve been getting notifications from StartSSL for a month saying that my SSL certificate is expiring. I decided to try out the new Let’s Encrypt free SSL. In this post I will be installing the certificate on a mail server. To start off, you will need Git on your server apt-get install git Next up, More…
Installing Varnish cache on Ubuntu 14.04 and measuring performance with ApacheBench
Today I’m doing an assignment for my school’s linux servers class held by Tero Karvinen. The assignment is to install Varnish cache and edit the settings of it, to measure site speed with ‘ab’ (ApacheBench) included in ‘apache2-utils’ package and to analyze and speed up a site with Firebug. I will do this assignment with More…
Installing WordPress along with plugins, themes and images
In this post, I’m doing an assignment for the linux server course held by Tero Karvinen. I’m going to install wordpress to my virtual private server on Amazon EC2, which I created earlier. I will be using a MacBook Pro (late 2013) as a terminal and the Amazon EC2 virtual server as the server. The server More…
Setting up a free virtual server with Amazon EC2 and a .tk domain
In this post I’m doing an assignment for Tero Karvinen’s course on linux servers. The assignment is to create a name based virtual server with a domain pointing to it. I decided to use Amazon’s EC2, since it has a free tier and I have already used it once before. Setting up Once I already More…
Building and installing a ‘.deb’ package that adds an executable script to all users
This is a part two (link to part one) for my home assignment for Tero Karvinen’s course on linux servers. On this part I will build and install a package that will add an executable shell script and an alias for it for all users. Now to create a new package with a shell script More…
Building a metapackage and a local package repository
In this post I’m doing a home assignment for Tero Karvinen’s course of linux servers. The assignment is to build a metapackage that installs a bunch of software in a single package, to create a local package repository and to package a script so it installs a new command to all users. I’m going to do this More…
Protecting your SSH server from brute force attacks
If your server is online and out there, it’s probably being already attacked by someone with brute force. This means that someone is running a script trying to guess your root password so it can use your hardware for benefit. I ran into this problem recently after just weeks of publishing my website. You can More…
Solving Honeynet scan of the month 15
In this post I’m doing an assignment given by Tero Karvinen on his Linux server course about computer forensics by solving one of the honeynet scan of the month. I’m going to do this on my desktop computer. The computer is i5-3570k (4X, 3,8GHz, 6M) 16GB RAM, 2x Asus GeForce GTX 560 TI in SLI mode. Using More…
Analyzing and stressing Ubuntu 14.04 with munin and stress
Hello! In this post I’m doing an assignment for my Linux course in my school held by Tero Karvinen using Xubuntu 14.04.3 LTS. I will be using the same installation I used in the previous post on VirtualBox. To get started, I needed to install munin. It requires Apache to work, which I had already. Installing Munin sudo apt-get update More…