You got a irregularly high amount of traffic coming into your server. So much, in fact, that it's slowing down your server and other clients are timing out trying to access it. Looks like you're under a DDoS attack. DDoS, or destributed denial of service, is a specific way to attack and distabilize a server, by flooding it with traffic from one or more sources.
In the vast majority of cases, servers tend to get broken into for the following reasons:
As a systems administrator, it's your job to keep tabs on your server. To address the first point, keeping up with antivirus definitions updates and making sure you have the latest service packs for your software, get creative with passwords and change them regularly. Do everything you can to address the above concerns before a breach happens.
But what do we do once we know we have a breach?
This is entirely a tutorial article. We're mostly going to give you a summary of GIT and walk you through installing it on Centos and configuring it to work with GITHUB.
GIT is a version control tool that helps you to maintain and sync versions of things like files, directories, or code between between developers and teams. People use it to make sure everyone is working on the same version of code, to track changes and maintain progress. GIT is reliable, widely used, open and free! So let's take you through the setup.
It's fairly common to encounter a problem when setting up a private email server; your outgoing email sometimes gets classified as spam. WHOOPS!
Well we're here to help you avoid this awkward situation!
Chances are that if you found this page through a Google search, you're probably looking for information on how addressing and routing actually works, without getting too deep into the complicated, underlying logic and binary math that serves as the foundationg for modern networking. At some point, I was looking for just this kind of information and ended up spending untold hours poring through texts trying to put it all together. So my goal with this article, is to save you as much time as possible. However, because it's so fundamental to routing, avoiding math entirely won't be possible.
A few articles back, we discussed server disk performance and how to quickly troubleshoot its issues.
Let's go over some of the basics, just to refresh your memory. Chances are, you were probably more concerned about space requirements than performance. If you server application works, then it's all good right? Well, not so fast.
Depending on what you're using, you’ll probably need to as much as 30-50% overhead storage than the raw amount of storage your data will EVER use just to maintain optimum disk performance. This is basically how ZFS, or most copy-on-write file systems, are set up. With more traditional storage solutions you have a few more options, but you still need to understand exactly how much room you have to work with.
If you have no idea how to go about figuring out how much overhead you need, well - that's why we wrote this article! Read on.
LVM - Logical Volume Manager - tools used to create and manage logical volumes.
When you attach a new hard drive to your Linux system, you'll likely need to create new particions and volumes. To do that, we're going to work with LVM; a system that came about to solve many of the problems of traditional partitioning which is too rigid by comparison. Being able to quickly create, increase or decrease, and copy a volume is not something available to us with the old particioning method.
We've written a tutorial before on a simple setup of OpenVPN on a server which allows clients to connect to your server quickly and easily. For the sake of simplicity, that article omitted to mention a a whole lot of other useful settings for OpenVPN. So let's fix that!
In our last article we covered basic MySQL server replication using the master-slave configuration, using it to create reserve database copies, and running resource intensive queries.
This configuration has a few relatively obvious limitations.
Rsnapshot is a simple and powerful backup tool used for local or remote file and directory synchronization over rsync with differential backup support. Why not just use rsync? With rsync you would have to write your own scripts, usually using with complex logic to handle file rotation, errors, resource consumption etc, while rsnapshot has already been written for you- it`s a well-known, stable, easy-maintenance utility that's already included in many Linux distributions by default.
In this article, I`ll show you how to make a remote backup of your files with rsnapshot and a remote sudo user.