GRE tunneling from your DDoS Filtered VPS IP

Source: http://wiki.buyvm.net/doku.php/gre_tunnel

 Please consider  DDoS Protected VPS for your needs. 

Tutorial: GRE tunneling from your  DDoS Filtered VPS IP

What is a GRE tunnel?

Much like a proxy, a GRE tunnel allows you to pass traffic from your  VPS including DDoS filtering to another remote destination.

GRE tunnels allow all traffic through, not just HTTP. With a GRE tunnel you can serve, and deliver any type of content from any type of server (audio, FTP, SSH, SCP, video, etc.).

What can your use a GRE tunnel for?

GRE tunneling is very handy when you want to use our DDoS filtering services to protect services that are too large to host with us (I.e. game servers, Java applications, large database driven applications, etc.).

 

Don’t have root access for your destination server or are running a huge Windows deployment? Check out our alternative method to redirect traffic to your remote server.

Note: If you are tunneling to an OVH server, you most likely don’t have GRE support in your kernel. You’ll need to use a IPIP tunnel instead.

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How To Install and Configure VNC Remote Access for the GNOME Desktop on CentOS 7

Introduction

VNC or Virtual Network Computing is a platform-independent protocol that enables users to connect to a remote computer system and use its resources from a Graphical User Interface (GUI).

It’s like remote controlling an application: the client computer’s keystrokes or mouse clicks are transmitted over the network to the remote computer. VNC also allows clipboard sharing between both computers. If you come from a Microsoft Windows server background, VNC is much like the Remote Desktop Service, except it’s also available for OS X, Linux, and other operating systems.

Like everything else in the networking world, VNC is based on the client server model: VNC server runs on a remote computer — your Droplet — which serves incoming client requests.

Goals

In this tutorial we will learn how to install and configure a VNC server on CentOS 7. We will install the TigerVNC server which is freely available from the TigerVNC GitHub repository.

To demonstrate how VNC works, we will also install the GNOME desktop on your CentOS server. We will create two user accounts and configure VNC access for them. We will then test their connectivity to the remote desktop, and finally, learn how to secure the remote connection through an SSH tunnel. Continue reading

How To Install Java on CentOS and Fedora

Introduction

This tutorial will show you how to install Java on CentOS 7 (also 5, 6, 6.5), Fedora 20, and RHEL. Java is a popular software platform that allows you to run Java applications and applets.

The installation of the following versions of Java are covered:

  • OpenJDK 7
  • OpenJDK 6
  • Oracle Java 8
  • Oracle Java 7

Feel free to skip to your desired section using the Contents button on the sidebar!

Prerequisites

Before you begin this guide, you should have a regular, non-root user with sudo privileges configured on both of your servers–this is the user that you should log in to your servers as. You can learn how to configure a regular user account by following steps 1-4 in our initial server setup guide for Ubuntu 14.04.

Variations of Java

There are three different editions of the Java Platform: Standard Edition (SE), Enterprise Edition (EE), and Micro Edition (ME). This tutorial is focused on Java SE (Java Platform, Standard Edition).

There are two different Java SE packages that can be installed: the Java Runtime Environment (JRE) and the Java Development Kit (JDK). JRE is an implementation of the Java Virtual Machine (JVM), which allows you to run compiled Java applications and applets. JDK includes JRE and other software that is required for writing, developing, and compiling Java applications and applets.

There are also two different implementations of Java: OpenJDK and Oracle Java. Both implementations are based largely on the same code but OpenJDK, the reference implementation of Java, is fully open source while Oracle Java contains some proprietary code. Most Java applications will work fine with either but you should use whichever implementation your software calls for.

You may install various versions and releases of Java on a single system, but most people only need one installation. With that in mind, try to only install the version of Java that you need to run or develop your application(s).

Install OpenJDK 7

This section will show you how to install the prebuilt OpenJDK 7 JRE and JDK packages using the yum package manager, which is similar to apt-get for Ubuntu/Debian. OpenJDK 7 is the latest version of OpenJDK.

Install OpenJDK 7 JRE

To install OpenJDK 7 JRE using yum, run this command:

sudo yum install java-1.7.0-openjdk

At the confirmation prompt, enter y then RETURN to continue with the installation.

Congratulations! You have installed OpenJDK 7 JRE.

Install OpenJDK 7 JDK

To install OpenJDK 7 JDK using yum, run this command:

sudo yum install java-1.7.0-openjdk-devel

At the confirmation prompt, enter y then RETURN to continue with the installation.

Congratulations! You have installed OpenJDK 7 JDK.

Install OpenJDK 6

This section will show you how to install the prebuilt OpenJDK 6 JRE and JDK packages using the yum package manager.

Install OpenJDK 6

To install OpenJDK 6 JRE using yum, run this command:

sudo yum install java-1.6.0-openjdk

At the confirmation prompt, enter y then RETURN to continue with the installation.

Congratulations! You have installed OpenJDK 6 JRE.

Install OpenJDK 6 JDK

To install OpenJDK 6 JDK using yum, run this command:

sudo yum install java-1.6.0-openjdk-devel

At the confirmation prompt, enter y then RETURN to continue with the installation.

Congratulations! You have installed OpenJDK 6 JDK.

Install Oracle Java 8

This section of the guide will show you how to install Oracle Java 8 update 60 JRE and JDK (64-bit), the latest release of these packages at the time of this writing.

Note: You must accept the Oracle Binary Code License Agreement for Java SE, which is one of the included steps, before installing Oracle Java.

Install Oracle Java 8 JRE

Note: If you would like to install a different release of Oracle Java 8 JRE, go to the Oracle Java 8 JRE Downloads Page, accept the license agreement, and copy the download link of the appropriate Linux .rpm package. Substitute the copied download link in place of the highlighted part of the wget command.

Change to your home directory and download the Oracle Java 8 JRE RPM with these commands:

cd ~
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" \
"http://download.oracle.com/otn-pub/java/jdk/8u60-b27/jre-8u60-linux-x64.rpm"

Then install the RPM with this yum command (if you downloaded a different release, substitute the filename here):

sudo yum localinstall jre-8u60-linux-x64.rpm

Now Java should be installed at /usr/java/jdk1.8.0_60/jre/bin/java, and linked from /usr/bin/java.

You may delete the archive file that you downloaded earlier:

rm ~/jre-8u60-linux-x64.rpm

Congratulations! You have installed Oracle Java 8 JRE.

Install Oracle Java 8 JDK

Note: If you would like to install a different release of Oracle Java 8 JDK, go to the Oracle Java 8 JDK Downloads Page, accept the license agreement, and copy the download link of the appropriate Linux .rpm package. Substitute the copied download link in place of the highlighted part of the wget command.

Change to your home directory and download the Oracle Java 8 JDK RPM with these commands:

cd ~
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u60-b27/jdk-8u60-linux-x64.rpm"

Then install the RPM with this yum command (if you downloaded a different release, substitute the filename here):

sudo yum localinstall jdk-8u60-linux-x64.rpm

Now Java should be installed at /usr/java/jdk1.8.0_60/jre/bin/java, and linked from /usr/bin/java.

You may delete the archive file that you downloaded earlier:

rm ~/jdk-8u60-linux-x64.rpm

Congratulations! You have installed Oracle Java 8 JDK.

Install Oracle Java 7

This section of the guide will show you how to install Oracle Java 7 update 79 JRE and JDK (64-bit).

Note: You must accept the Oracle Binary Code License Agreement for Java SE, which is one of the included steps, before installing Oracle Java.

Install Oracle Java 7 JRE

Note: If you would like to install a different release of Oracle Java 7 JRE, go to the Oracle Java 7 JRE Downloads Page, accept the license agreement, and copy the download link of the appropriate Linux .rpm package. Substitute the copied download link in place of the highlighted part of the wget command.

Change to your home directory and download the Oracle Java 7 JRE RPM with these commands:

cd ~
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jre-7u79-linux-x64.rpm"

Then install the RPM with this yum command (if you downloaded a different release, substitute the filename here):

sudo yum localinstall jre-7u79-linux-x64.rpm

Now Java should be installed at /usr/java/jdk1.7.0_79/jre/bin/java, and linked from /usr/bin/java.

You may delete the archive file that you downloaded earlier:

rm ~/jre-7u79-linux-x64.rpm

Congratulations! You have installed Oracle Java 7 JRE.

Install Oracle Java 7 JDK

Note: If you would like to install a different release of Oracle Java 7 JDK, go to the Oracle Java 7 JDK Downloads Page, accept the license agreement, and copy the download link of the appropriate Linux .rpm package. Substitute the copied download link in place of the highlighted part of the wget command.

Change to your home directory and download the Oracle Java 7 JDK RPM with these commands:

cd ~
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-x64.rpm"

Then install the RPM with this yum command (if you downloaded a different release, substitute the filename here):

sudo yum localinstall jdk-7u79-linux-x64.rpm

Now Java should be installed at /usr/java/jdk1.7.0_79/jre/bin/java, and linked from /usr/bin/java.

You may delete the archive file that you downloaded earlier:

rm ~/jdk-7u79-linux-x64.rpm

Congratulations! You have installed Oracle Java 7 JDK.

Set Default Java

If you installed multiple versions of Java, you may want to set one as your default (i.e. the one that will run when a user runs the java command). Additionally, some applications require certain environment variables to be set to locate which installation of Java to use. This section will show you how to do this.

By the way, to check the version of your default Java, run this command:

java -version

Using Alternatives

The alternatives command, which manages default commands through symbolic links, can be used to select the default Java command.

To print the programs that provide the java command that are managed by alternatives, use this command:

sudo alternatives --config java

Here is an example of the output:

There are 5 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
*+ 1           /usr/java/jdk1.8.0_60/jre/bin/java
   2           /usr/java/jdk1.7.0_79/jre/bin/java


Enter to keep the current selection[+], or type selection number: 

Simply enter the a selection number to choose which java executable should be used by default.

Using Environment Variables

Many Java applications use the JAVA_HOME or JRE_HOME environment variables to determine which java executable to use.

For example, if you installed Java to /usr/java/jdk1.8.0_60/jre/bin (i.e. java executable is located at /usr/java/jdk1.8.0_60/jre/bin/java), you could set your JAVA_HOME environment variable in a bash shell or script like so:

export JAVA_HOME=/usr/java/jdk1.8.0_60/jre

If you want JAVA_HOME to be set for every user on the system by default, add the previous line to the /etc/environment file. An easy way to append it to the file is to run this command:

sudo sh -c "echo export JAVA_HOME=/usr/java/jdk1.8.0_60/jre >> /etc/environment"

Conclusion

Congratulations, you are now set to run and/or develop your Java applications!

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Secure Your Apache With mod_security

This article shows how to install and configure mod_security. mod_security is an Apache module (for Apache 1 and 2) that provides intrusion detection and prevention for web applications. It aims at shielding web applications from known and unknown attacks, such as SQL injection attacks, cross-site scripting, path traversal attacks, etc. Continue reading