Usually it becomes difficult to handle HTTP flood attacks,the reason being the lack of way to identify legitimate packets from the ones which are sent by the hacker,hence it is difficult to tackle such situation. The servers TCP/IP stack isn’t the only target,the prime target of HTTP flood ddos attack is the web server too that runs on it thus it results in more serious attack which is not easy to handle and your server may crash down resulting in its inaccessibility.

Though we say that it is difficult to tackle such attacks,but it isn’t impossible.There exists a solution for handling such HTTP flood ddos attack.

There exists an advanced technique known as “Tarpitting” which is an efficient counter acting method to fight against such attacks.Incase you are using a Linux based server, you can enable Tarpitting using the below command :

iptables -A INPUT -s x.x.x.x -p tcp -j TARPIT

Tarpitting automatically sets connections window size to few bytes once established successfully. According to TCP/IP protocol design, the connecting device will initially only send as much data to target as it takes to fill the window until the server responds. Just incase the connecting device does not receive responses, it will repeatedly start sending packets for longer period of time.
Here plays the actual role of ” tarpitting “,it won’t respond back to the packets, hence protecting your server from getting unwanted HTTP requests.

Inorder to avoid such attacks and threats,it is important to choose the Best Web Hosting services from a reputed web hosting company.No matter if you have a small business web hosting package or a Dedicated server hosting account,if you are using the services of a reliable web hosting provider,their technical expertise can help you counter act such attacks with minimum waste of time resulting in the least loss to your server.

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Debian operating systems can be referred as the flavor of the Linux operating systems or to make it simple it can also be called as the version of the Linux operating systems.As the Debian operating system is the flavor of the Linux operating system it also uses the same kernel which is used by the Linux operating system. Linux operating system and Debian operating system both use the Linux kernel at present.Linux kernel is developed by  Linus Trovalds.The word Linux also comes from the founder of the Linux Kernel Linus Trovalds.After the development of the Linux Kernel Linus Trovalds became the chief architect of the Linux operating system.GNU is also an operating system and the utilities and the libraries of the Linux operating system usually come from the GNU operating system.GNU operating system is a part of the GNU project and was announced by Richard Stallman ( Owner of the GNU project ).This is the reason why the name GNU/Linux is used.

At the moment Debian operating system only uses Linux kernel but the project is under development to provide Debian for the Hurd which is also a Kernel.The Hurd is free software produced by the GNU project and is a collection of Dedicated servers that run on top of a microkernel (such as Mach) to implement different features.Debian operating system is very good for people who are looking for a software for editing documents,to run a business,play games or for writing more soft wares. Moreover it is free and Debian comes with over 18733 packages. Debian runs on maximum computer system that is even if you have an older one then it might be possible that you can use Debian.Debian is free but buying CD’s or bandwidth might cost you as Debian is free but the medium through which you are taking or installing Debian operating system cost’s.You can install Debian and use it and if you need support it will be provided by the documentation on the website or with the packages of Debian.It is also possible to contact the Debian team with the help of mails or IRC.Due to all these benefits Debian is used by many individuals and organizations around the globe.Apart from this ,Debian also has something which can be considered as a benefit and a drawback.Debian is a bit difficult to use than the Linux operating system.Due to this it is very difficult for a user to use Debian if the user is new to it.To use Debian the user should have good knowledge about computers and Debian.But as Debian is difficult to use than Linux it is much more secured than Linux.

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The following things are required if you want to install cPanel and WHM:

-One of the supported operating systems basic server install.

-As cPanel and WHM will not run without a license file a cpanel license is a necessary.( A license from an authorized cpanel distributor or partner can be obtained along with a free 15-day test license )

Before Beginning :-

A blank Dedicated server with a fresh operating system install is a must as cpanel and WHM can only be installed on it.The Dedicated server should have no data that you want to keep. Web pages, configuration files, user accounts and scripts are included in this but are not limited.Some other type of data also cannot be kept. Many changes to your system will be made by your installer.This also includes the downloading and configuring of the packages you need. Due to all these changes made on your Dedicated server as you have installed the cpanel you are suggested to reformat the server if you want to uninstall the cPanel and WHM software.

Fresh installation with minimal installation options is suggested.wget and development tool libraries are also required.

-As MySQL, Apache, exim, PHP, etc will be installed by cPanel and WHM it is necessary that you install any    of these services beforehand.

-Make sure that package management (or ports) system is properly configured (yum, apt-get, up2date, ports).

-Also ensure that /etc/resolv.conf contains valid name-Dedicated servers that allow you to resolve domains properly.

Example > You can also test this, try: dig domain.com @serverip

SYNTAX : Replace “domain.com” with the name of a well known domain and replace “serverip” with the IP address of a name-server in “/etc/resolv.conf”

A fully qualified domain name that will not be used elsewhere on the server should be the hostname of this server.Already used hostname should never be set by you to a name that is already used (www, ftp, mail, etc) or to the name of an account on the server (www.domain.com).Your hostname should never be a domain name and especially not the name of your domain!!This is what the above written words mean.

If you think that installation for you should be done by cPanel, Inc and you have already obtained a license then, you may request it.IP address, the root password of your Dedicated server and the operating system installed on the server should also be provided.

NOTE : Different partition schemes are suitable for different types of hosting.To be allocated in different ways than others some servers may require space.This recommended scheme is an attempt to provide enough space for many different types of hosting but it is no substitution for real world experience. This partition scheme may need to be varied to suit the needs of your specific setup.

The “/tmp” directory is a special directory that is required to be writable by all users and processes on the system. In general, directories that are writable by all users and processes are a cause for security concern, however this directory is a special case. To minimize any security impact as a result of having an unsecured directory will verify and potentially remount the partition with the “no exec” option. Additionally, the installer will ensure that the sticky bit is set on the directory and that the other permissions are correct. If “/tmp” is not mounted on a separate partition, the installer will create a file system disk image of 512 MB and mount “/tmp” on the newly created disk image with the “no exec” directive. Under most circumstances, 512 MB is sufficient for the “/tmp” partition; however, your system may require additional space. It is therefore recommended that you include a separate partition for the “/tmp” mount point (sized according to your size specification) prior to installing cPanel.

Custom Configurations

Number of tools are provided by the cPanel within the cPanel and WHM Software to handle custom server and client configurations.Tools like those in our EasyApache system which allow you to configure modules, compile options, httpd.conf modifications, etc.

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World’s most popular open source database software is MySQL.MySQL AB is a swedish company which owns MySQL.It is a single for-profit firm and now is a subsidiary of Sun Microsystems which holds the copywrite to most of the codebase.If you are looking for a stable database platform for your organisation having an excellent speed and reliability but you cannot afford the main stream products from microsoft and oracle? then MySQL is the answer for you.MySQL is not a difficult task for you even if you are a new user as it is very simple to use.MySQL:the complete reference is the book by Vikram Vasvani which is a complete reference book for MySQL and it can be very useful to you if you are a new user to MySQL.The book is comprehensive enough and has a wonderful technical reference which can help you out if you are a new or a seasoned user for MySQL.

MySQL acts as the database component and is also popular for web application.It acts as the database component of the LAMP,BAMP,MAMP and WAMP platforms (Linux/BSD/Mac/Windows,Apache,MySQL,PHP/Perl/Python) and it also does not require complex scripting or programming.

Setup:-

HOWTO set up a MySQL Cluster for two Dedicated Servers (three servers required for true redundancy)

Introduction

This HOWTO was designed for a classic setup of two Dedicated Servers behind a loadbalancer. The aim is to have true redundancy – the site will still remain up even if either server is unplugged which can be done.

Notes:

You MUST have a third server as a management node but this can be shut down after the cluster starts. Also note that shutting down the management server is not recommended (see the extra notes at the bottom of this document for more information). You can not run a MySQL Cluster with just two Dedicated servers And have true redundancy.

Although it is possible to set the cluster up on two physical Dedicated Serversyou WILL NOT GET the ability to “kill” one server and for the cluster to continue as normal. For this you need a third server running the managment node.

I am going to talk about three servers:

mysql1.domain.com 		192.168.0.1
mysql2.domain.com 		192.168.0.2
mysql3.domain.com 		192.168.0.3

Servers 1 and 2 will be the two that end up “clustered”. This would be perfect for two servers behind a loadbalancer or using round robin DNS and is a good replacement for replication. Server 3 needs to have only minor changes made to it and does NOT require a MySQL install. It can be a low-end machine and can be carrying out other tasks.

STAGE 1: Install MySQL on the first two servers:

Complete the following steps on both mysql1 and mysql2:

cd /usr/local/
http://dev.mysql.com/get/Downloads/MySQL-4.1/mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz/
	from/http://www.signal42.com/mirrors/mysql/
groupadd mysql
useradd -g mysql mysql
tar -zxvf mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz
rm mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz
ln -s mysql-max-4.1.9-pc-linux-gnu-i686 mysql
cd mysql
scripts/mysql_install_db --user=mysql
chown -R root  .
chown -R mysql data
chgrp -R mysql .
cp support-files/mysql.server /etc/rc.d/init.d/
chmod +x /etc/rc.d/init.d/mysql.server
chkconfig --add mysql.server

Do not start mysql yet.

STAGE 2: Install and configure the managment server

You need the following files from the bin/ of the mysql directory: ndb_mgm and ndb_mgmd. Download the whole mysql-max tarball and extract them from the bin/ directory.

mkdir /usr/src/mysql-mgm
cd /usr/src/mysql-mgm
http://dev.mysql.com/get/Downloads/MySQL-4.1/mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz/
	from/http://www.signal42.com/mirrors/mysql/
tar -zxvf mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz
rm mysql-max-4.1.9-pc-linux-gnu-i686.tar.gz
cd mysql-max-4.1.9-pc-linux-gnu-i686
mv bin/ndb_mgm .
mv bin/ndb_mgmd .
chmod +x ndb_mg*
mv ndb_mg* /usr/bin/
cd
rm -rf /usr/src/mysql-mgm

You now need to set up the config file for this managment:

mkdir /var/lib/mysql-cluster
cd /var/lib/mysql-cluster
vi [or emacs or any other editor] config.ini

Now, insert the following (changing the bits as indicated):

[NDBD DEFAULT]
NoOfReplicas=2
[MYSQLD DEFAULT]
[NDB_MGMD DEFAULT]
[TCP DEFAULT]
# Managment Server
[NDB_MGMD]
HostName=192.168.0.3		# the IP of THIS SERVER
# Storage Engines
[NDBD]
HostName=192.168.0.1		# the IP of the FIRST SERVER
DataDir= /var/lib/mysql-cluster
[NDBD]
HostName=192.168.0.2		# the IP of the SECOND SERVER
DataDir=/var/lib/mysql-cluster
# 2 MySQL Clients
# I personally leave this blank to allow rapid changes of the mysql clients;
# you can enter the hostnames of the above two servers here. I suggest you dont.
[MYSQLD]
[MYSQLD]

Now, start the managment server:

ndb_mgmd

This is the MySQL management server, not maganment console. You should therefore not expect any output (we will start the console later).

STAGE 3: Configure the storage/SQL servers and start mysql

On each of the two storage/SQL servers (192.168.0.1 and 192.168.0.2) enter the following (changing the bits as appropriate):

vi /etc/my.cnf

Enter i to go to insert mode again and insert this on both servers (changing the IP address to the IP of the managment server that you set up in stage 2):

[mysqld]
ndbcluster
ndb-connectstring=192.168.0.3	# the IP of the MANAGMENT (THIRD) SERVER
[mysql_cluster]
ndb-connectstring=192.168.0.3	# the IP of the MANAGMENT (THIRD) SERVER

Now, we make the data directory and start the storage engine:

mkdir /var/lib/mysql-cluster
cd /var/lib/mysql-cluster
/usr/local/mysql/bin/ndbd --initial
/etc/rc.d/init.d/mysql.server start

If you have done one server now go back to the start of stage 3 and repeat exactly the same procedure on the second server.

Note: you should ONLY use --initial if you are either starting from scratch or have changed the config.ini file on the managment.

STAGE 4: Check its working

You can now return to the managment server (mysql3) and enter the managment console:

/usr/local/mysql/bin/ndb_mgm

Enter the command SHOW to see what is going on. A sample output looks like this:

[root@mysql3 mysql-cluster]# /usr/local/mysql/bin/ndb_mgm
-- NDB Cluster -- Management Client --
ndb_mgm> show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=2    @192.168.0.1  (Version: 4.1.9, Nodegroup: 0, Master)
id=3    @192.168.0.2  (Version: 4.1.9, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @192.168.0.3  (Version: 4.1.9)

[mysqld(API)]   2 node(s)
id=4   (Version: 4.1.9)
id=5   (Version: 4.1.9)

ndb_mgm>

If you see

not connected, accepting connect from 192.168.0.[1/2/3]

in the first or last two lines they you have a problem. Please email me with as much detail as you can give and I can try to find out where you have gone wrong and change this HOWTO to fix it.

If you are OK to here it is time to test mysql. On either server mysql1 or mysql2 enter the following commands: Note that we have no root password yet.

mysql
use test;
CREATE TABLE ctest (i INT) ENGINE=NDBCLUSTER;
INSERT INTO ctest () VALUES (1);
SELECT * FROM ctest;

You should see 1 row returned (with the value 1).

If this works,which will probably happen, go to the other server and run the same SELECT and see what you get. Insert from that host and go back to host 1 and see if it works. If it works then congratulations.

The final test is to kill one server to see what happens. If you have physical access to the machine simply unplug its network cable and see if the other server keeps on going fine (try the SELECT query). If you dont have physical access do the following:

ps aux | grep ndbd

You get an output like this:

root      5578  0.0  0.3  6220 1964 ?        S    03:14   0:00 ndbd
root      5579  0.0 20.4 492072 102828 ?     R    03:14   0:04 ndbd
root     23532  0.0  0.1  3680  684 pts/1    S    07:59   0:00 grep ndbd

In this case ignore the command “grep ndbd” (the last line) but kill the first two processes by issuing the command kill -9 pid pid:

kill -9 5578 5579

Then try the select on the other server. While you are at it run a SHOW command on the managment node to see that the server has died. To restart it, just issue

ndbd

Note: no --inital!

Further notes about setup

I strongly recommend that you read all of this (and bookmark this page). It will almost certainly save you a lot of searching.

The Managment Server

I strongly recommend that you do not stop the management server once it has started. This is for several reasons:

• The server might hardly require and take any server resources
• If a cluster falls over, you want to be able to just ssh in and type ndbd to stat it. You wil not want to start messing around with another server
• You need the management server up If you want to take backups
• The cluster log is sent to the management server so to check what is going on in the cluster or has happened since last this is an important tool
• All commands from the ndb_mgm client is sent to the management server and thus no management commands without management server.
• The managment server is required in case of cluster reconfiguration (crashed server or network split). In the case that it is not running, “split-brain” scenario will occur. The management server arbitration role is required for this type of setup to provide better fault tolerance.

However you are welcome to stop the server if you prefer.

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To solve this problem you have to improve the Dedicated server scalability.The respond time of the server being slow is due to the number of HTTP requests made at the same time for the site hosted on a particular server is much more than the server capacity to respond to the requests.For this reason there are many Dedicated servers needed so that the load which is on a particular server gets distributed among a number of servers and there is an increase in the scalability.This process of distributing the load so as to increase the scalability is called clustering.The load distribution among the servers is called as load balancing.Load balancing is applied to both database as well as application servers.

Load balancing mechanism :-

The HTTP requests made are to be evenly distributed when there are multiple servers in the group.IP Spraying is the load balancing mechanism which is used for distributing the HTTP requests among the servers.It acts like a single server to the clients as an internet browser.The equipments used for Ip spraying which can even be called as “Load balancers” are “Load dispatcher” and “network dispatcher”.HTTP requests are redirected to a server in the server cluster by the IP Sprayer.Type of IP sprayer is very important as all this depends on it so that more scalability and load balancing is provided by the architecture so that it can overcome all the fail-over requirements.

To get a rough idea of the structure of the load balanced server you can have a look at one of the load balanced server.

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First step is to find the source codes and the following link will help you for this purpose.What you need to do is get the source codes for the PHP package and then you have to compile the package from scratch here, and, while there are also binary packages available for some distributions, I find your end results are usually better when building each package for your machine. Make sure you get the source files.The current version available is 5.2.6  :-

LINK: http://www.php.net/downloads.php
Current Version available – 5.2.6

So I hope that you have got the source codes.Now the installation begins…

The first thing you have to do for the installing PHP is to extract the source-codes so that you will be able to work with the files included in them.for this you will be working as root to Begin,for this you will have to open a terminal window and change to the directory in which you saved your downloaded files and become root by issuing the su command.After this enter the root password and you will be able to go.

Type the following command to get the source codes….

#tar -zxf php-5.2.6.tar.gz (enter)

The commands above will extract the sourcecodes into the directory.

Change into the PHP source directory as follows;

Compiling PHP :-

Once the prompt comes type the following command ;

#make (enter)

Wait for the time till you have the prompt.After getting the prompt you will have to give the following command ;

#make install (enter)

Once the install finishes and you have the prompt type the following command;

#cp php.ini-recommended /usr/local/php/lib/php.ini (enter)

Then edit the file;

#vi /usr/local/php/lib/php.ini (enter)

And edit the following;

Find the doc_root section and enter the correct path for the directory which serves your web content, such as ;

Then find the file_uploads section and change it to reflect the following;

file_uploads=Off

(for security reasons)

Now you have done it.

Testing –

You can check whether your work is done or not with the help of the following :-

Using vi create a file called test.php;

#vi test.php

Add the following line to the file;

<?php phpinfo(); ?>

Save the file, then fire up your browser and point it to localhost/test.php

I hope this has helped and you have successfully installed PHP on your dedicated server.

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