Windows Server 2012 KMS Service Activation

Now we have the Windows Server 2012 and Windows 8 RTM bit form our Volume License we need to get some housekeeping done. The first thing we do is setup or update our KMS Service.
In our case it is running on Windows Server 2008 R2 so we need to do a couple of things.
Install the following update: An update is available for Windows 7 and Windows Server 2008 R2 KMS hosts to support Windows 8 and Windows Server 2012 as described in KB2691586. This is also the place where you can request this hotfix.  If you don’t install this hotfix registering a Windows Server 2012  KMS will throw an Error: 0xC004F050 The Software Licensing Service reported that the product key is invalid
So request the hotfix and install it from an elevated command prompt. Just follow the instructions and you’ll be fine

Once you’ve clicked OK the installation will start

After that’s finished you will be asked to restart the server. Do so. Just restarting the KMS service ("net stop sppsvc" and "net start sppsvc") doesn’t suffice.

Now we have that out the way we can start putting our brand new KMS key into action.
Let’s take a look at what is already running:
slmgr.vbs /dlv => clearly the Windows 2008 R KMS key

Uninstall the current KMS key using slmgr.vbs /upk, please use an elevated command prompt


Now you can install the new KMS key. The key listed here is obviously a demo one If you run in to any issues here, restarting the KMS Service can help. Try that first.
slmgr.vbs /ipk NOPEI-AMNOT-GIVIN-GITTO-YOU!!


Now activate your brandnew KMS key running slmgr.vbs /ato


Show what’s up and running now by running slmgr.vbs /dlv again and as you can see we’re in business to activate all our Windows Server 2012 and Windows 8 hosts. Life is good

 

Source : https://blog.workinghardinit.work/2012/08/17/windows-server-2012-kms-service-activation/

How To Setup a Firewall with UFW on an Ubuntu and Debian Cloud Server

Introduction

One of the first lines of defense in securing your cloud server is a functioning firewall. In the past, this was often done through complicated and arcane utilities. There is a lot of functionality built into these utilities, iptables being the most popular nowadays, but they require a decent effort on behalf of the user to learn and understand them. Firewall rules are not something you want yourself second-guessing.
To this end, UFW is a considerably easier-to-use alternative.

What is UFW?

UFW, or Uncomplicated Firewall, is a front-end to iptables. Its main goal is to make managing your firewall drop-dead simple and to provide an easy-to-use interface. It’s well-supported and popular in the Linux community—even installed by default in a lot of distros. As such, it’s a great way to get started securing your sever.

Before We Get Started

First, obviously, you want to make sure UFW is installed. It should be installed by default in Ubuntu, but if for some reason it’s not, you can install the package using aptitude or apt-get using the following commands:

sudo aptitude install ufw

or

sudo apt-get install ufw

Check the Status

You can check the status of UFW by typing:

sudo ufw status

Right now, it will probably tell you it is inactive. Whenever ufw is active, you’ll get a listing of the current rules that looks similar to this:

Status: active

To               Action      From
--               ------      ----
22               ALLOW       Anywhere

Using IPv6 with UFW

If your VPS is configured for IPv6, ensure that UFW is configured to support IPv6 so that will configure both your IPv4 and IPv6 firewall rules. To do this, open the UFW configuration with this command:

sudo vi /etc/default/ufw

Then make sure "IPV6" is set to "yes", like so:

IPV6=yes

Save and quit. Then restart your firewall with the following commands:

sudo ufw disable
sudo ufw enable

Now UFW will configure the firewall for both IPv4 and IPv6, when appropriate.

Set Up Defaults

One of the things that will make setting up any firewall easier is to define some default rules for allowing and denying connections. UFW’s defaults are to deny all incoming connections and allow all outgoing connections. This means anyone trying to reach your cloud server would not be able to connect, while any application within the server would be able to reach the outside world. To set the defaults used by UFW, you would use the following commands:

sudo ufw default deny incoming

and

sudo ufw default allow outgoing

Note: if you want to be a little bit more restrictive, you can also deny all outgoing requests as well. The necessity of this is debatable, but if you have a public-facing cloud server, it could help prevent against any kind of remote shell connections. It does make your firewall more cumbersome to manage because you’ll have to set up rules for all outgoing connections as well. You can set this as the default with the following:

sudo ufw default deny outgoing

Allow Connections

The syntax is pretty simple. You change the firewall rules by issuing commands in the terminal. If we turned on our firewall now, it would deny all incoming connections. If you’re connected over SSH to your cloud server, that would be a problem because you would be locked out of your server. Let’s enable SSH connections to our server to prevent that from happening:

sudo ufw allow ssh

As you can see, the syntax for adding services is pretty simple. UFW comes with some defaults for common uses. Our SSH command above is one example. It’s basically just shorthand for:

sudo ufw allow 22/tcp

This command allows a connection on port 22 using the TCP protocol. If our SSH server is running on port 2222, we could enable connections with the following command:

sudo ufw allow 2222/tcp

Other Connections We Might Need

Now is a good time to allow some other connections we might need. If we’re securing a web server with FTP access, we might need these commands:
sudo ufw allow www or sudo ufw allow 80/tcp sudo ufw allow ftp or sudo ufw allow 21/tcp
You mileage will vary on what ports and services you need to open. There will probably be a bit of testing necessary. In addition, you want to make sure you leave your SSH connection allowed.

Port Ranges

You can also specify port ranges with UFW. To allow ports 1000 through 2000, use the command:

sudo ufw allow 1000:2000/tcp

If you want UDP:

sudo ufw allow 1000:2000/udp

IP Addresses

You can also specify IP addresses. For example, if I wanted to allow connections from a specific IP address (say my work or home address), I’d use this command:

sudo ufw allow from 192.168.255.255

Denying Connections

Our default set up is to deny all incoming connections. This makes the firewall rules easier to administer since we are only selectively allowing certain ports and IP addresses through. However, if you want to flip it and open up all your server’s ports (not recommended), you could allow all connections and then restrictively deny ports you didn’t want to give access to by replacing “allow” with “deny” in the commands above. For example:

sudo ufw allow 80/tcp

would allow access to port 80 while:

sudo ufw deny 80/tcp

would deny access to port 80.

Deleting Rules

There are two options to delete rules. The most straightforward one is to use the following syntax:

sudo ufw delete allow ssh

As you can see, we use the command “delete” and input the rules you want to eliminate after that. Other examples include:

sudo ufw delete allow 80/tcp

or

sudo ufw delete allow 1000:2000/tcp

This can get tricky when you have rules that are long and complex.
A simpler, two-step alternative is to type:

sudo ufw status numbered

which will have UFW list out all the current rules in a numbered list. Then, we issue the command:

sudo ufw delete [number]

where “[number]” is the line number from the previous command.

Turn It On

After we’ve gotten UFW to where we want it, we can turn it on using this command (remember: if you’re connecting via SSH, make sure you’ve set your SSH port, commonly port 22, to be allowed to receive connections):

sudo ufw enable

You should see the command prompt again if it all went well. You can check the status of your rules now by typing:

sudo ufw status

or

sudo ufw status verbose

for the most thorough display.
To turn UFW off, use the following command:

sudo ufw disable

Reset Everything

If, for whatever reason, you need to reset your cloud server’s rules to their default settings, you can do this by typing this command:

sudo ufw reset

Conclusion

You should now have a cloud server that is configured properly to restrict access to a subset of ports or IP addresses.

 

Article Submitted by: Shaun Lewis

 

Source : https://www.digitalocean.com/community/tutorials/how-to-setup-a-firewall-with-ufw-on-an-ubuntu-and-debian-cloud-server

XenServer 6.2: How to set up passthrough of a PCI or PCI-Express device

 This is done by logging in as the root user to your XenServer system via SSH. To see the PCI devices available to your system, enter the following command:

lspci

Here is an example result:

00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 Northbridge only dual slot (2×16) PCI-e GFX Hydra part (rev 02) 00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD/ATI] RD990 I/O Memory Management Unit (IOMMU) 00:02.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 PCI to PCI bridge (PCI express gpp port B) 00:09.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 PCI to PCI bridge (PCI express gpp port H) 00:0a.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 PCI to PCI bridge (external gfx1 port A) 00:0b.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890 PCI to PCI bridge (NB-SB link) 00:0c.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] RD890S PCI Express bridge for GPP2 port 1 00:11.0 SATA controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode] 00:12.0 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB OHCI0 Controller 00:12.1 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0 USB OHCI1 Controller 00:12.2 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB EHCI Controller 00:13.0 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB OHCI0 Controller 00:13.1 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0 USB OHCI1 Controller 00:13.2 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB EHCI Controller 00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD/ATI] SBx00 SMBus Controller (rev 3d) 00:14.1 IDE interface: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 IDE Controller 00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 LPC host controller 00:14.4 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] SBx00 PCI to PCI Bridge 00:14.5 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] SB7x0/SB8x0/SB9x0 USB OHCI2 Controller 00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 0 00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 1 00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 2 00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 3 00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 4 00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 5 00:19.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 0 00:19.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 1 00:19.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 2 00:19.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 3 00:19.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 4 00:19.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 5 00:1a.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 0 00:1a.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 1 00:1a.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 2 00:1a.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 3 00:1a.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 4 00:1a.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 5 00:1b.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 0 00:1b.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 1 00:1b.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 2 00:1b.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 3 00:1b.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 4 00:1b.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 15h Processor Function 5 01:01.0 VGA compatible controller: ASPEED Technology, Inc. ASPEED Graphics Family (rev 10) 01:03.0 Multimedia audio controller: C-Media Electronics Inc CMI8788 [Oxygen HD Audio] 02:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection 03:00.0 Multimedia controller: Philips Semiconductors SAA7164 (rev 81) 04:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection 05:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection 06:00.0 InfiniBand: Mellanox Technologies MT26418 [ConnectX VPI PCIe 2.0 5GT/s – IB DDR / 10GigE] (rev b0)

As you might guess from some of the lines, it’s an AMD server. You’ll notice some USB controllers, likely a SATA controller and any PCI or PCI Express add-in cards (usually at the bottom). In this example we will pass through a digital TV card to a VM so we can record free-to-air TV. The controller here is the fourth-last entry:

03:00.0 Multimedia controller: Philips Semiconductors SAA7164 (rev 81)

It’s a Digital Now PCI-E card – as you can see there’s no mention of the brand in the chipset that the system can see, so you may have to make an educated guess (or do some research as to what’s actually used in the card) to determine which one you want. Making note of the above line, we now edit /boot/extlinux.conf:

vi /boot/extlinux.conf

In our example system it looks like this:

# location mbr serial 0 115200 default xe prompt 1 timeout 50 label xe # XenServer kernel mboot.c32 append /boot/xen.gz mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 console=vga vga=mode-0x0311 — /boot/vmlinuz-2.6-xen root=LABEL=root-ckwntldj ro xencons=hvc console=hvc0 console=tty0 quiet vga=785 splashi  — /boot/initrd-2.6-xen.img label xe-serial # XenServer (Serial) kernel mboot.c32 append /boot/xen.gz com1=115200,8n1 console=com1,vga mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 — /boot/vmlinuz-2.6-xen root=LABEL=root-ckwntldj ro console=tty0 xencons=hvc console=hvc0 — /boot/initrd-2.6-xen.img label safe # XenServer in Safe Mode kernel mboot.c32 append /boot/xen.gz nosmp noreboot noirqbalance acpi=off noapic mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M com1=115200,8n1 console=com1,vga — /boot/vmlinuz-2.6-xen nousb root=LABEL=root-ckwntldj ro console=tty0 xencons=hvc console=hvc0 — /boot/initrd-2.6-xen.img label fallback # XenServer (Xen 4.1.5 / Linux 2.6.32.43-0.4.1.xs1.8.0.835.170778xen) kernel mboot.c32 append /boot/xen-4.1.5.gz mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 — /boot/vmlinuz-2.6.32.43-0.4.1.xs1.8.0.835.170778xen root=LABEL=root-ckwntldj ro xencons=hvc console=hvc0 console=tty0 — /boot/initrd-2.6.32.43-0.4.1.xs1.8.0.835.170778xen.img label fallback-serial # XenServer (Serial, Xen 4.1.5 / Linux 2.6.32.43-0.4.1.xs1.8.0.835.170778xen) kernel mboot.c32 append /boot/xen-4.1.5.gz com1=115200,8n1 console=com1,vga mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 — /boot/vmlinuz-2.6.32.43-0.4.1.xs1.8.0.835.170778xen root=LABEL=root-ckwntldj ro console=tty0 xencons=hvc console=hvc0 — /boot/initrd-2.6.32.43-0.4.1.xs1.8.0.835.170778xen.img

Rather an intimidating-looking file if you’re new to *nix config files. Fortunately, we can ignore most of this and just pay attention to the last line in the “label xe” section at the top. The line we want to edit is:

append /boot/xen.gz mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 console=vga vga=mode-0x0311 — /boot/vmlinuz-2.6-xen root=LABEL=root-ckwntldj ro xencons=hvc console=hvc0 console=tty0 quiet vga=785 splashi  — /boot/initrd-2.6-xen.img

Looking at the line we wanted from lspci above, we want the number at the front – in this case:

03:00.0

Add the following near the end of the config line – inbetween “splashi” and “—“:

pciback.hide=(03:00.0)

 The line should now read:

append /boot/xen.gz mem=1024G dom0_max_vcpus=4 dom0_mem=4096M,max:4096M watchdog_timeout=300 lowmem_emergency_pool=1M crashkernel=64M@32M cpuid_mask_xsave_eax=0 console=vga vga=mode-0x0311 — /boot/vmlinuz-2.6-xen root=LABEL=root-ckwntldj ro xencons=hvc console=hvc0 console=tty0 quiet vga=785 splashi pciback.hide=(03:00.0) — /boot/initrd-2.6-xen.img

Note the space on either side – one between splashi and the new text and one between the hyphens and the new text. Now run:

extlinux -i /boot

Then shut down any VMs and reboot the server:

reboot

Once it is back up, we need to find the UUID of the virtual machine we want to pass the device through to. Run:

xe vm-list

This will return a result for every VM on the system – it might be quite long! If it is a long list you may wish to pipe it to the less command for easier viewing:

xe vm-list | less

If you aren’t familiar with less you can exit with the “q” key. Sort through the list until you find the VM you want to pass through to. In this example it is:

uuid ( RO)           : 6b664553-6822-b445-5a8c-c10d93c41c4c name-label ( RW): bacchus power-state ( RO): halted

Now we can add the PCI device to the config of this VM:

xe vm-param-set other-config:pci=0/0000:03:00.0 uuid=6b664553-6822-b445-5a8c-c10d93c41c4c

Breaking that down:

xe vm-param-set other-config:pci=0/0000:[PCI address for the device] uuid=[UUID of VM]

Starting the VM – in this case a Windows 7 VM – we can check for the device to see that it has appeared (in this case the drivers were already installed so it has been immediately identified):



Success! In a Linux system you should be able to do:

lspci

 to see the newly passed through hardware.

Source : http://www.sotechdesign.com.au/xenserver-6-2-how-to-set-up-passthrough-of-a-pci-or-pci-express-device/

How to Setup XenServer 6.x to Auto-Start Virtual Machines

Objective

In XenServer versions 6.x, the direct GUI ability to auto-start a Virtual Machine on the startup of XenServer was removed. This article describes how to set Virtual Machines to auto-start.

Requirements

XenServer version 6.x

Background

In XenServer 6.x, the auto-start functionality was removed because it interfered with High Availability (HA) and produced unexpected results during HA functions.

---

Instructions

Setting the XenServer to allow Auto-Start

1. Gather the UUIDs of the pools you wish to auto-start.
   
2. To get the list of the pools on your XenServer, run “xe pool-list”
   
3. Copy the UUID of the pool. If you have just one server, it will still have a pool UUID as noted in the following
   
   
   
4. Then type the following command to set the pool or server to allow auto-start:
   xe pool-param-set uuid=UUID other-config:auto_poweron=true
   Note: Replacing UUID with the UUID of the XenServer or pool.
   

Setting the Virtual Machines to Auto-Start

1. Gather the UUIDs of the Virtual Machine you want to auto-start by running xe vm-list.
   Note: This generates a list of Virtual Machines in your pool or server and their associated UUIDs.
   
2. Copy the UUID of the Virtual Machines you want to auto-start, and run the following command for each Virtual Machine to auto-start:
   xe vm-param-set uuid=UUID other-config:auto_poweron=true
   Note: Replace UUID with the UUID of the Virtual Machine to auto-start. 

 Source : http://support.citrix.com/article/CTX133910

How to Install and Configure phpMyAdmin on CentOS 6

phpMyAdmin is an open source tool used for the administration of MySQL. In addition to offering the capability to perform administration tasks such as creating, editing, or deleting databases, and managing users and permissions, phpMyAdmin provides a graphical user interface to do all of these tasks and more.

Pre-Flight Check

• These instructions are intended specifically for installing phpMyAdmin on CentOS 6.
• I’ll be working from a Liquid Web Core Managed CentOS 6.5 server, and I’ll be logged in as root.
• A LAMP, Linux, Apache, MySQL and PHP, must be installed on your server. If you’re working from a Liquid Web Core Managed CentOS 6.5 server as I am, then the LAMP stack is already installed!

Step 1: Add the EPEL Repository

phpMyAdmin is part of Extra Packages for Enterprise Linux (EPEL), which is a community repository of non-standard packages for the RHEL distribution. First, we’ll install the EPEL repository:

rpm -iUvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

Step 2: Install phpMyAdmin

First, you’ll follow a simple best practice: ensuring the list of available packages is up to date before installing anything new.

yum -y update

Then it’s a matter of just running one command for installation via apt-get:

yum -y install phpmyadmin

Step 3: Find Your IP Address

Find your IP address with any of the following sites:

• What’s My IP Address?
• What Is My IP?
• My IP Address

Step 4: Basic Configuration for phpMyAdmin

To secure phpMyAdmin we should lock down access to a specific IP address. When the phpMyAdmin package is installed, an Apache Virtual Host file is added to configure web access. Let’s edit that file:
vim /etc/httpd/conf.d/phpMyAdmin.conf
For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor
By default, the configuration for phpMyAdmin only allows access from the server on which it is installed. Find the following sections and change each IP address to the one you found in Step 3, or another IP address that will be connecting to phpMyAdmin remotely:
Require ip 127.0.0.1
Allow from 127.0.0.1
Require ip 127.0.0.1
Allow from 127.0.0.1

Then exit and save the file with the command :wq .
Restart Apache:

service httpd restart

Verify that phpMyAdmin is working by visiting http://the_IP_of_your_server/phpmyadmin. For example: http://127.0.0.1/phpmyadmin

source : http://www.liquidweb.com/kb/how-to-install-and-configure-phpmyadmin-on-centos-6/

how to check OS and version using Console

# cat /etc/*release*

# cat /etc/redhat-release 

# cat /proc/version

# cat /etc/issue

# lsb_release -a  

# cat /etc/lsb-release 

# cat /etc/issue.net

# cat /etc/debian_version 

Resize EC2 instance EBS root device

Today I stumbled upon the problem that resizing the root EBS volume of a just launched EC2 instance (running CentOS 6) did not work.

I tried to run the following command:"resize2fs /dev/xvde1"
This returned with:The filesystem is already x blocks long. Nothing to do!

However I was pretty sure that there was still roughly 1TB extra available for me. I figured out how to resolve this, with the following commands:
1. Connect to the instance over ssh2. "fdisk /dev/xvde1"3. Press "p" + ENTER to view the current partitions, remember the ID of your partition4. Fill in "d 999", where 999 represents the partition ID from step 3, hit ENTER (this will delete your partition)5. Press "n" + ENTER to start creating a new partition6. Press "p" + ENTER to mark it as a primary partition7. Select the first cylinder by entering "1" and hitting ENTER8. Your start and end block can be default (e.g. 1 and 1234567)9. Press "a" to mark the partition as bootable10. Now we're done press "w" to write the partition table, this will cause you to get an error, don't worry11. Reboot your instance to reload the partition table (as mentioned in the error you received on step 10)12. Connect to your instance again over ssh13. Run "resize2fs /dev/xvde1", this might take a while, it performs an online grow of the partition14. Once the resize2fs command has finished you can validate the results by running "df -h"
Good luck with resizing your EC2 instance root devices!

Source : http://www.robinverlangen.nl/index/view/5035f20d64fa0-d74cc2/resize-ec2-instance-ebs-root-device.html

Versi lain
=========

1. Stop the instance
 2. Create a snapshot from the volume
 3. Create a new volume based on the snapshot increasing the size
 4. Check and remember the current's volume mount point (i.e. /dev/sda1)
 5. Detach current volume
 6. Attach the recently created volume to the instance, setting the exact mount point
 7. Restart the instance
 8. Access via SSH to the instance and run fdisk /dev/xvde
 9. Hit **p** to show current partitions
 10. Hit **d** to delete current partitions (if there are more than one, you have to delete one at a time) NOTE: Don't worry data is not lost
 11. Hit **n** to create a new partition
 12. Hit **p** to set it as primary
 13. Hit **1** to set the first cylinder
 14. Set the desired new space (if empty the whole space is reserved)
 15. Hit **a** to make it bootable
 16. Hit **1** and **w** to write changes
 17. Reboot instance
 18. Log via SSH and run resize2fs /dev/xvde1
 19. Finally check the new space running df -h

Source : http://stackoverflow.com/questions/11014584/ec2-cant-resize-volume-after-increasing-size

Add Another Local Disk on XenServer as a new Storage Repository

from xenserver console:

fdisk -l

that should return an error like this:

Disk /dev/sdb doesn't contain a valid partition table

your local hard drive is "/dev/sdb" or whatever the error the first command shows you

run this command

xe host-list

that will return something like this:
uuid ( RO) : 3614fba9-f5fc-1c57-0b42-58513c51fc1c
name-label ( RW): xenb
name-description ( RO): Default install of XenServer

copy the UUID of your host server to the clipboard.


xe sr-create host-uuid=<your host UUID> content-type=user type=lvmohba device-config:device=/dev/sdb shared=false name-label="Local_Stor_2"

if you get an error you may need to unmount your current local storage in order to add the new one.
to do this, run this command:

xe pbd-list

get the UUID of your current storage

run this:
xe pbd-unplug uuid=<your storage UUID>

then try mounting your Hardware HBA through Xencenter.
This worked for me, hope it does for you too

Source : http://www.serveroperations.net/citrix/add-another-local-disk-on-xenserver-as-a-new-storage-repository

Mikrotik Cloud – a Dynamic DNS name and NTP service

When you setup a router in a site that does not have a static public IP address, you would usually have to rely on 3rd party Dynamic DNS services to provide you access to the device/site without knowing the current IP address.  This involved running scripts on the router to constantly update the DNS records.
Starting with RouterOS 6.14, Mikrotik have added a new feature called Cloud.¬†When enabled, it will generate a DNS name based on your router’s serial number. It also provides an NTP service. This will avoid having to run scripts to update the ip address if you use ntp servers like¬†ntp.pool.org and will not require any script to update the ip address at the 3rd party dynamic DNS name providers. Agreed, the generated DNS name is not a friendly one since it is based on the serial no but it should not be something you need to remember regularly since you can save the details in winbox.
To enable the Cloud service through command line:

/ip cloud set enabled=yes

To enable the NTP service (Update Time):

/ip cloud set update-time=yes

To view the settings and note the DNS Name:

/ip cloud print

The output will be similar to the below:

enabled: yes
update-time: yes
public-address: 0.0.0.0
dns-name: serialnumber.sn.mynetname.net
status: updated

Please note: Since v6.27 /ip cloud set enabled has changed to
/ip cloud set ddns-enabled
You can also enable it through Winbox or Webbox by clicking on the IP menu and click on Cloud.

Then tick the box marked Enabled and Update Time, if you require time sync. As soon as you click Apply, your DNS Name will be generated and it will show the current Public IP address

I personally like these new features and will definitely make use of them.
This seems to be a very popular post with daily hits. Don’t be shy! Let me know if you find it useful or if something needs to be changed!
UPDATE: I have written a blog post for using the Mikrotik Cloud IP DDNS when you have multiple ISPs. You can find it here.

Source = http://www.phy2vir.com/mikrotik-cloud-a-dynamic-dns-name-and-ntp-service/

How To Setup Your Own VPN With PPTP

Intro

One of the commonly asked questions from our users is how to add another IP address to their server. You can assign your own private IP address to your droplet by creating a VPN tunnel. Whether you want to build your own Virtual Private Network (VPN), or assign an SSL certificate to that IP address, you have several options. From all of the possible options, the most optimal ones are between PPTP and OpenVPN. A Point-To-Point Tunneling Protocol (PPTP) allows you to implement your own VPN very quickly, and is compatible with most mobile devices. Even though PPTP is less secure than OpenVPN, it is also faster and uses less CPU resources.

Step 1 - PPTP Installation

You will have to select one server to be responsible for handling out IPs to others and authenticating all of your servers into your VPN. This will become your PPTP Server.
On CentOS 6 x64:

rpm -i http://poptop.sourceforge.net/yum/stable/rhel6/pptp-release-current.noarch.rpm
yum -y install pptpd

On Ubuntu 12.10 x64:

apt-get install pptpd

Now you should edit /etc/pptpd.conf and add the following lines:

localip 10.0.0.1
remoteip 10.0.0.100-200

Where localip is IP address of your server and remoteip are IPs that will be assigned to clients that connect to it.
Next, you should setup authentication for PPTP by adding users and passwords. Simply add them to /etc/ppp/chap-secrets : Where client is the username, server is type of service – pptpd for our example, secret is the password, and IP addresses specifies which IP address may authenticate. By setting ‘*’ in IP addresses field, you specify that you would accept username/password pair for any IP.

Step 2 - Add DNS servers to /etc/ppp/pptpd-options

ms-dns 8.8.8.8
ms-dns 8.8.4.4

Now you can start PPTP daemon:

service pptpd restart

Verify that it is running and accepting connections:

Step 3 - Setup Forwarding

It is important to enable IP forwarding on your PPTP server. This will allow you to forward packets between public IP and private IPs that you setup with PPTP. Simply edit /etc/sysctl.conf and add the following line if it doesn’t exist there already:

net.ipv4.ip_forward = 1

To make changes active, run sysctl -p

Step 4 - Create a NAT rule for iptables

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

If you would also like your PPTP clients to talk to each other, add the following iptables rules:

iptables --table nat --append POSTROUTING --out-interface ppp0 -j MASQUERADE
iptables -I INPUT -s 10.0.0.0/8 -i ppp0 -j ACCEPT
iptables --append FORWARD --in-interface eth0 -j ACCEPT

Now your PPTP server also acts as a router.
If you would like to restrict which servers can connect to your droplets, you can setup an iptables rule that restricts TCP connects to port 1723.

Step 5 - Setup Clients

On your client servers, install PPTP client:

yum -y install pptp

Step 6 - Add necessary Kernel module

modprobe ppp_mppe

Create a new file /etc/ppp/peers/pptpserver and add the following lines, replacing name and password with your own values:

pty "pptp 198.211.104.17 --nolaunchpppd"
name box1
password 24oiunOi24
remotename PPTP
require-mppe-128

Where 198.211.104.17 is the public IP address of our PPTP server, with username ‘box1’ and password ‘24oiunOi24’ that we specified /etc/ppp/chap-secrets file on our PPTP server.
Now we can ‘call’ this PPTP server, since this is a point-to-point protocol. Whichever name you gave your peers file in/etc/ppp/peers/ should be used in this next line. Since we called our file pptpserver:

pppd call pptpserver

You should see successful connection from PPTP server logs:
On your PPTP client, setup routing to your private network via ppp0 interface:

ip route add 10.0.0.0/8 dev ppp0

Your interface ppp0 should come up on PPTP client server, and can be checked by running ifconfig
Now you can ping your PPTP server and any other clients that are connected to this network:
We can add our second PPTP client to this network:

yum -y install pptp
modprobe ppp_mppe

Add to /etc/ppp/peers/pptpserver (replacing with your own name and password values):

pty "pptp 198.211.104.17 --nolaunchpppd"
name box2
password 239Aok24ma
remotename PPTP
require-mppe-128

Now run on your second client the following:

pppd call pptpserver
ip route add 10.0.0.0/8 dev ppp0

You can also ping the first client, as packets would go through the PPTP server and be routed using the iptables rules we’ve placed earlier:
This setup allows you to create your own virtual private network:
If you wanted to have all of your devices communicating securely on one network, this is a quick way of implementing it.
You can use it with Nginx, Squid, MySQL, and any other application you can think of.
Since traffic is 128-bit encrypted, it is less CPU-intensive than OpenVPN, and still provides an added level of security to your traffic.

Source = https://www.digitalocean.com/community/tutorials/how-to-setup-your-own-vpn-with-pptp

Pengertian dan Konsep RAID

RAID merupakan kependekan dari “Redundant Array of Independent Disk”. Konsep RAID diciptakan untuk mendapatkan kapasitas yang lebih besar dan/atau Fault tolerance yang disebabkan oleh kerusakan Harddisk. Fault Tolerance adalah kemampuan dari suatu system untuk dapat tetap berfungsi meskipun mengalami kegagalan.
Fault tolerance dalam suati server dapat berupa:
• Redundant Power supply (power supply cadangan)
• Redundant FAN
• Online spare (Memory & HDD)
• Mirroring (Memory & HDD)
• RAID 1, RAID 5, dan RAID 6

RAID 0 (Disk Striping)
Disk Striping mengijinkan kita untuk menulis data ke beberapa Harddisk daripada menulis data ke satu Harddisk saja. Dengan Disk Striping, setiap Harddisk fisik akan dibagi menjadi beberapa elemen stripe (berkisar antara 8 KB, 16 KB, 32 KB, 64 KB, 128 KB, 256KB, 512KB, to 1024KB). Setiap bagian stripe dalam setiap Harddisk disebut strip.
Disk Striping dapat meningkatkan kinerja karena pengaksesan data diakses dengan lebih dari satu harddisk, sehingga lebih banyak spindle disk yang bekerja dalam melayani I/O data. Namun Disk Striping (RAID 0) tidak memiliki data redundancy / proteksi data terhadap kerusakan harddisk, karena semua data ditulis langsung apa adanya ke semua Harddisk.

Dari sisi kapasitas, maka RAID 0 kita dapat menggunakan 100% dari total jumlah kapasitas harddisk yang terpasang.
Contoh: 4 unit Harddisk 300GB RAID 0 akan menghasilkan total kapasitas yang dapat digunakan sebesar
1.2TB

RAID 1 (Disk Mirroring)
RAID 1 (Disk Mirroring) bekerja dengan prinsip cermin, yaitu berpasang-pasangan dan identik antara satu dengan yang lainnya. Jadi dengan RAID 1, data yang ditulis ke satu Harddisk secara simultan ditulis juga ke Harddisk yang lainnya. Sehingga jika terjadi kerusakan 1 Harddisk pada RAID 1, system server masih memiliki data cadangan di harddisk yang lainnya. Dan pada saat Harddisk yang rusak diganti dengan yang baru, maka secara otomatis, harddisk pengganti yang baru dipasang akan melakukan sinkronisasi data dengan harddisk yang masih berfungsi (rebuilding) Keuntungan dari RAID 1 adalah data memiliki cadangan antara yang ada di harddisk yang satu dengan yang lainnya. Dan karena isi dari kedua Harddisk tersebut adalah identik, tidak jadi masalah harddisk yang mana yang boleh rusak selama pada suatu saat hanya satu Harddisk yang rusak, sampai proses sinkronisasi berikutnya selesai.

Dari sisi kapasitas, maka RAID 1 kita akan hanya memiliki kapasitas harddisk yang dapat digunakan sebanyak 50% dari total kapasitas Harddisk yang terpasang
Contoh: 4 unit Harddisk 300GB RAID 1 akan menghasilkan total kapasitas yang dapat digunakan sebesar 600GB.

RAID 5 (Disk Striping with Distributed Parity)
Sesuai dengan namaya, cara kerja RAID 5 sama dengan cara kerja RAID 0, yaitu menggunakan disk striping.Yang membedakan anatara keduanya adalah Parity. Parity ini digunakan untuk pengecekan dan perbaikan kesalahan (error checking and correcting). Parity ini disebar di beberapa disk untuk menghindari pengurangan kinerja (Performance bottleneck) pada saat pembuatan parity. Jika Parity disimpan di satu harddisk saja, maka disebut RAID 3 (Disk Striping with Dedicated Parity). Dengan adanya parity ini, maka system RAID 5 tersebut akan tetap berfungsi jika ada salah satu harddisk dalam RAID 5 tersebut itu rusak. Dan harddisk yang rusak tersebut dapat harddisk yang mana saja selama berada dalam satu system RAID 5 yang sama. Karena parity ini berasal dari perhitungan matematik dari suatu beberapa pecahan data, maka, pada saat ada satu bagian pecahan data yang hilang/rusak, system RAID 5 dapat “mengetahui” pecahan data yang hilang tesebut dengan menghitung ulang parity dengan pecahan data yang lainnya.
Secara sederhana, parity bisa dianalogikan dengan perhitungan matematik sbb; 6 + 5 = 11. Dimana angka 6 & 5 adalah data, dan angka 11 adalah parity. Jika suatu saat angka (Harddisk) 5 mengalami kerusakan, maka system dapat menghitung ulang berdasarkan parity (angka 11), angka(Harddisk) apa yang hilang tersebut. Jadi data yang ada pada harddisk yang rusak, tetaplah rusak, hanya saja dengan bantuan parity maka data pada harddisk yang hilang tersebut dapat dihitung ulang kembali. Hal ini juga yang menyebabkan untuk RAID 5 mengalami kerusakan harddisk adalah sebanyak 1 harddisk saja pada suatu saat.Kembali dengan analogi matematik diatas, jika angka (Harddisk) 6 + 5 hilang, maka kemungkinan angka 11 didapat bisa memiliki banyak kemungkinan, seperti 2+9, 3 + 8, dst. komputer tidak dapat membuat suatu perhitungan yang tepat jika data yang tersedia memiliki banyak kemungkinan.

Dari sisi kapasitas, maka RAID 5 kita akan memiliki kapasitas harddisk yang dapat digunakan sebanyak (N-1) x Kapasitas HDD dari total kapasitas Harddisk yang terpasang, dimana N adalah jumlah Harddisk.
Contoh:
• 3 unit Harddisk 300GB RAID 5 akan menghasilkan total kapasitas yang dapat digunakan sebesar 600GB.
• 4 unit Harddisk 300GB RAID 5 akan menghasilkan total kapasitas yang dapat digunakan sebesar 900GB.
• 5 unit Harddisk 300GB RAID 5 akan menghasilkan total kapasitas yang dapat digunakan sebesar 1.2TB, dst.

RAID 6 (Disk Striping with Dual Parity)
(*mulai didukung HANYA di PERC6 dan selanjutnya)
Dapat dilihat dari namanya, RAID 6 menggunakan cara kerja dan konsep yang sama dengan RAID 5 dari sisi penulisan data yang tersebar di beberapa hard disk. Yang membedakan antara RAID 6 dan RAID 5 adalah jumlah parity yang ditulis pada saat penulisan data. Jika RAID 5 menggunakan satu parity, maka RAID 6 menggunakan dua parity. Dengan menulis 2 parity, maka RAID 6 dapat mengakomodasikan kerusakan harddisk maksimal 2 unit pada saat yang bersamaan

Dari sisi kapasitas, maka RAID 6 kita akan memiliki kapasitas harddisk yang dapat digunakan sebanyak (N-2) x Kapasitas HDD dari total kapasitas Harddisk yang terpasang, dimana N adalah jumlah Harddisk.
Contoh:
• 4 unit Harddisk 300GB RAID 6 akan menghasilkan total kapasitas yang dapat digunakan sebesar 600GB.
• 5 unit Harddisk 300GB RAID 6 akan menghasilkan total kapasitas yang dapat digunakan sebesar 900GB.
• 6 unit Harddisk 300GB RAID 6 akan menghasilkan total kapasitas yang dapat digunakan sebesar 1.2TB, dst.
Sekian pembahasan tentang RAID, semoga bermanfaat.

Source : https://nasari.wordpress.com/2010/04/30/pengertian-raid/

Open Port 25 to All

[root@server mail]# netstat -vatn

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN 

After looking through several files I discovered how to fix it:
First you need to edit /etc/mail/sendmail.mc, find the following section:
dnl This changes sendmail to only listen on the loopback device 127.0.0.1 dnl and not on any other network devices. Comment this out if you want dnl to accept email over the network. DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

You will need to comment out the like with DAEMON_OPTIONS, using "dnl" at the begining of the line:
dnl This changes sendmail to only listen on the loopback device 127.0.0.1 dnl and not on any other network devices. Comment this out if you want dnl to accept email over the network. dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')

You will then need to restart sendmail

/etc/init.d/sendmail restart

Once you have done this sendmail will listen on all IP address on the system:

[root@server mail]# netstat -vatn
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:25              0.0.0.0:*               LISTEN 

And you can recieve mail from others, and send mail from your clients.

Installing FFMpeg

yum install ffmpeg ffmpeg-devel

If you get package not found, then you will need to add few lines in the yum repository for dag packages installation. Create a file named  /etc/yum.repos.d/dag.repo with the following contents on it

[dag]
name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
gpgcheck=1
enabled=1

then

yum install ffmpeg ffmpeg-devel

Linux Change Default User Home Directory While Adding A New User

By default base directory for the system user is set to /home directory. I'd like to add user to /iscsi/home/${user} directory instead of the default /home. How do I force useradd command to add user to /iscsi/home under CentOS / RHEL / Fedora Linux server?

Default values for account creation defined in /etc/default/useradd file under CentOS / RHEL / Fedora / Debian / Ubuntu and other Linux distros. Simply open this file using a text editor, type:
# vi /etc/default/useradd

The default home directory defined by HOME variable, find line that read as follows:
HOME=/home

Replace with:
HOME=/iscsi/user

Save and close the file. Now you can add user using regular useradd command:
# useradd vivek
# passwd vivek

Verify user information:
# finger vivek

Output:

Login: vivek                            Name: Vivek Gite
Directory: /iscsi/user/vivek                Shell: /bin/bash
Last login Thu Sep 13 07:58 2007 (IST) on pts/1 from 10.16.15.2
No mail.
No Plan.

How Do I Change Existing User's Home Directory?

You need to use the usermod command to set the user's new login directory. The syntax is as follows:

 
usermod -m -d /path/to/new/home/dir userNameHere
 

Where,

1. -d dirnanme : Path to new login (home) directory.
2. -m : The contents of the current home directory will be moved to the new home directory, which is created if it does not already exist.

In this example set the user's new login directory to /users/v/vivek from /home/vivek, enter:
# usermod -m -d /users/v/vivek vivek

 Source : http://www.cyberciti.biz/faq/howto-change-default-home-directory/

Firefox browser tool to test Responsive Web design

Modern web browsers are more developer friendly, by providing Developer Tools to make web development easy. Thanks to Mozilla for integrating a feature, which allows to test the Responsive Web design with out using various physical devices.
How to use Responsive Web Design feature in Firefox?

1. Launch Mozilla Firefox(Latest Version).
2. Browse the website which you wish to test. For example – i will take – http://tickletheweb.com website, which is developed to have consistent view across the devices.

3.   Click on Firefox button on the left top corner of the browser, and select Web Developer –> Responsive Design View.

4.  It loads the Responsive Design View chrome -

5.  Select different resolutions from the dropdown control on the left corner of the chrome to test the website in different resolutions, which is simple and great.

6.  It also allows to test  Portrait or Landscape orientations. Click on rotate button, which toggles between the orientations.

Happy Web programming!!!

Source : https://roopeshreddy.wordpress.com/2013/05/26/firefox-browser-tool-to-test-responsive-web-design/