Add Swap File on AWS EC2 Ubuntu Redhat Linux

Use following commands to create swap file on your system.

$ sudo dd if=/dev/zero of=/var/swapfile bs=1M count=2048

bs=1M count=2048 means it will create 2GB of swap file, You may change as per you need. After enabling swap we can see that our system has swap enabled by running “free -m” command.

To prevent the file from being world-readable, you should set up the correct permissions on the swap file:

$ sudo chown root:root /var/swapfile
$ sudo chmod 0600 /var/swapfile

Subsequently we are going to prepare the swap file by creating a linux swap area.

$ sudo mkswap /var/swapfile

Finish up by activating the swap file.

$ sudo swapon /var/swapfile

You will then be able to see the new swap file when you view the swap summary.

$ sudo swapon -s

This file will last on the virtual private server until the machine reboots. You can ensure that the swap is permanent by adding it to the fstab file.

$ sudo nano /etc/fstab

Paste in the following line:

/var/swapfile swap swap defaults 0 0

Ubuntu system comes with a default of 60, meaning that the swap file will be used fairly often if the memory usage is around half of my RAM. You can check your own system’s swappiness value by running:

$ cat /proc/sys/vm/swappiness

As I have 4 GB of RAM, so I’d like to turn that down to 10 or 15. The swap file will then only be used when my RAM usage is around 80 or 90 percent. To change the system swappiness value, open /etc/sysctl.conf as root. Then, change or add this line to the file:

vm.swappiness = 10

Reboot for the change to take effect.

You can also change the value while your system is still running

sysctl vm.swappiness=10

Skipping this step may cause both poor performance.

You can also clear your swap by running

swapoff -a

And then

swapon -a

As root instead of rebooting to achieve the same effect.

Create Own Private PPTP VPN Server on AWS EC2 Ubuntu Redhat

For Ubuntu Server,

$ sudo apt-get install pptpd ufw

For 32 bit Redhat instances,

$ wget http://poptop.sourceforge.net/yum/stable/rhel6/i386/pptpd-1.3.4-2.el6.i686.rpm
$ yum localinstall pptpd-1.3.4-2.el6.i686.rpm

For 64 bit Redhat instances,

$ wget http://poptop.sourceforge.net/yum/stable/rhel6/x86_64/pptpd-1.4.0-1.el6.x86_64.rpm
$ yum localinstall pptpd-1.4.0-1.el6.x86_64.rpm

If you are using uwf, please allow Ports 22 and 1723 on UFW and Enable UFW
Warning: if you are connected to SSH on a port other than 22, please adjust the first command accordingly so you don’t get kicked off.

$ sudo ufw allow 22
$ sudo ufw allow 1723
$ sudo ufw enable

Edit “/etc/ppp/pptpd-options”
Comment out (by placing a “#” at the beginning of the line) the following lines in “/etc/ppp/pptpd-options”:

#refuse-pap
#refuse-chap
#refuse-mschap

If you don’t want to require encryption, comment out “require-mppe-128” (might be good to disable it just for testing and re-enable it later)

Add the following:

ms-dns 8.8.8.8
ms-dns 8.8.4.4

*You can use any DNS servers you like, the two above are Google’s public DNS servers.

Edit “/etc/pptpd.conf”
At the end of the file “/etc/pptpd.conf”, add:

localip 172.16.0.5
remoteip 172.16.0.11-19

 

The localip field determines the IP address of your EC2 instance on the VPN, while remoteip field determines the IP address of connected clients. Because there may be potentially many clients connecting to this VPN, the remoteip is a range of 10 IP addresses.

Same edit “/etc/pptpd.conf”, Comment out logwtmp by adding # at the beginning of the line

#logwtmp

Edit “/etc/ppp/chap-secrets”
The format for “/etc/ppp/chap-secrets” is: [Username] [Service] [Password] [Allowed IP Address]
Add something like this to the end (replacing sampleusername and samplepassword with whatever you want):

sampleusername pptpd samplepassword *

Reboot pptpd
Finally, you can reboot the pptpd server with:

$ sudo /etc/init.d/pptpd restart

Edit “/etc/sysctl.conf”
Un-comment the following line in “/etc/sysctl.conf”:

net.ipv4.ip_forward=1

The following command reloads the configuration (you can also just reboot at the end of this guide):

$ sudo sysctl -p

And we also need to enable iptables NAT configuration:

$ iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

To ensure the NAT configuration be loaded when the machine boots, it might be a good idea to add in your “/etc/rc.local” the command:

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

OK, it’s nearly finished! You need to start the pptpd service, and set it to automatically start when the machine boots:

$ /sbin/service pptpd start
$ chkconfig pptpd on

ONE FINAL THING:
Be sure to enable port 1723 of your EC2 instance, otherwise the firewall will prevent your VPN from working!

MySQL create user with grant all privileges

Login to your MySQL

mysql -u root -p

Enter your MySQL root password.

GRANT ALL ON *.* TO 'username'@'localhost' IDENTIFIED BY 'password' WITH GRANT OPTION;
GRANT ALL ON *.* TO 'username'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
FLUSH PRIVILEGES;
EXIT;

New user with grant all privileges has been created successfully.

Redirect www to non www URL Using HTACCESS for WordPress

Learn to redirect www to non-www URLs or non www to www URLs using .htaccess file. You can do 301 permanent redirect on shared server with multiple domains also. If you have a self hosted WordPress website, you it would be useful for you.

mod_rewrite module of Apache server

Apache server uses modules for various functionalists. mod_rewrite is a module that enables redirection and URL rewriting. If this module is installed and available on Apache server, only then your redirection will work.

If mod_rewrite is available, it will take your redirection commands from .htaccess file.

Redirect old domain to new domain

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www.olddomainname.com$ [OR]
RewriteCond %{HTTP_HOST} ^olddomainname.com$
RewriteRule ^(.*)$ http://www.newdomainname.com/$1 [R=301,L]
</IfModule>

Redirect www to non-www URL Domain

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.example.com [NC]
RewriteRule ^(.*) http://example.com/$1 [L,R=301]
</IfModule>

Redirect non-www to www URL Domain

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} ^example.com [nocase]
RewriteRule ^(.*) http://www.example.com/$1 [last,redirect=301]
</IfModule>