Step-by-Step: DHCP High Availability with Windows Server 2012 R2

If you use the DHCP Role to provide IP addresses to your clients but don’t have a solid monitoring solution (System Center Operations Manager) you probably find out your DHCP server is down when all your customer start calling the help desk. And considering how business is more than ever about being connected and having access to the services and the data you need to get the job done. Any downtime is not a good thing.

In this Step-By-Step, we’ll take a look at setting up DHCP failover using Windows Server 2012 R2 which can be downloaded here. As always you can use the info in this post to setup your lab. (It was originally written for 2012 but the same steps work for 2012 R2)

In previous Windows versions like Windows Server 2008 R2 and Windows Server 2003, you have two options to make DHCP highly available:

• DHCP in a Windows failover cluster. This option places the DHCP server in a cluster with an additional server configured with the DHCP service that assumes the load if the primary DHCP server fails. The clustering deployment option uses a single shared storage. This makes the storage a single point of failure, and requires additional investment in redundancy for storage. In addition, clustering involves relatively complex setup and maintenance.
• Split scope DHCP. Split scope DHCP uses two independent DHCP servers that share responsibility for a scope. Typically 70% of the addresses in the scope are assigned to the primary server and the remaining 30% are assigned to the backup server. If clients cannot reach the primary server then they can get an IP configuration from the secondary server. Split scope deployment does not provide IP address continuity and is unusable in scenarios where the scope is already running at high utilization of address space, which is very common with Internet Protocol version 4 (IPv4).

Those were good, but not great solutions. In Windows Server 2012 DHCP Failover enables administrators to deploy a highly resilient DHCP service to support your business without the challenges of the 2 options discussed above. It provide DHCP service availability at all times on the enterprise network. If a DHCP server is no longer reachable, the DHCP client is able to extend the lease on its current IP address by contacting another DHCP server on the enterprise network.

DHCP failover architecture

There are also 2 way of making the DHCP role highly available. You can set it up your failover partners in hot standby mode or in load sharing mode.

Hot standby mode

In hot standby mode, an active server is responsible for providing IP addresses and configuration information to all clients in a scope or subnet and the secondary server assumes the responsibility if the primary server becomes unavailable. (Your Primary can also be the secondary for another scope and/or subnet which make this arrangement very well suited for environment where a central office or data center server acts as a standby backup server to a server at a remote site (ex: hub and spoke deployment).

Load sharing mode

In a load sharing mode, which is the default mode and the one we will setup in our lab, the two servers simultaneously serve IP addresses and options to clients on a given subnet. The client requests are load balanced and shared between the two servers.

I started with my lab where I have 4 servers and 3 client machines

1. DC1 (Domain Controller, DNS, File & Storage Services)
2. Lab-srv-1 (Cluster Node 1)
3. Lab-srv-2 (Cluster Node 2)
4. Lab-srv-3 (DHCP, System Center)
5. X201 (Windows 7 client)
6. Proman-RT (Windows 8.1 RT client)
7. Lab-pc-1 (Windows 8.1 client)

(For this Step-By-Step I will assume you already have a DHCP server already providing addresses to your clients.)

We will install the DHCP role on DC1 and make it highly available.

1. In Server Manager, under Manage, click Add Roles and Features.
2. In the Add Roles and Features Wizard, click Next twice and then ensure that you are installing the role on DC1, and then after clicking Next again, on the Select server roles page select the DHCP Server checkbox.
3. When you are prompted to add required features, click Add Features.
4. Click Next three times, and then click Install.
5. Wait for the installation process to complete, under the Notification area click Complete DHCP configuration.
6. In the DHCP Post-Install Configuration wizard, click Next in the Description page, Commit in the Authorization page and then Close to complete the installation.

To configure DHCP on DC1.contoso.com. (Our scope is already created on Lab-srv-3)

1. On the Server Manager menu bar, click Tools and then click DHCP.
2. Right Click DHCP and select Add Server
3. Type the name of the other DHCP server already on your network in our case Lab-srv-3
4. In the DHCP console tree on the server that already has the configured scope Lab-srv-3, navigate to IPv4. Right-click IPv4 and then click Configure Failover.
5. In the Configure Failover wizard, review the available subnets and check the select all box and click Next.
6. In the specify the Failover partner screen click the Add Server button, and type the name of the partner in the “This Server” field. In our case DC1 and click ok and Next
7. In the Create a new failover relationship, validate the info already populated. Leave all settings as default including the Mode drop box that is setup as ‘load Balance” and enter a Shared Secret password or code. In our case enter P@ssw0rd, click Next
8. Click Finish to complete the configuration
9. Review the confirmation screen and click Close.

That’s it you are done. Now if either lab-srv-3 or DC1 fails the clients on my network will continue to receive their IP configuration information from a DHCP server.

Step-by-step samba server configuration for windows sharing.

1.Server  IP address is 192.168.0.254 and machine name is SERVER1.
2.Windows machine IP address is 192.168.0.2 and machine name is client2.
3.Firewall Should be disabled.
 #chkconfig iptables off
 #service iptables stop
 #chkconfig ip6tables off
 #service ip6tables  stop
4.To check if all rpms required for samba are installed or not.
 #rpm –qa | grep samba
 Samba-<version-name>
 Samba-common-<version-name>
 Samba-client-<version- name>
 System-config-samba-<version-name>
5.If not, install it using
 #rpm –ivh samba

6.Copy the original configuration file as smb.conf.bck
 #cp /etc/samba/smb.conf /etc/samba.conf.bck
 (This will keep a backup copy of your configuration file.)

7.Now edit the configuration file
 #vi /etc/samba/smb.conf

8.To share home directory edit this part of /etc/samba/smb.conf
 [homes]
 comment=Home directories
 browseable =no
 writable=yes

9.To share printer edit this part of  /etc/samba/smb.conf
 [printers]
 comment = All printers
 path = /var/spool/samba
 browseable = no

10.To configure share called SYSSTEC edit this part of /etc/samba/smb.conf
 [SYSSTEC share]
 comment = Testing Samba Server
 path  = /samba
 valid users = user1, user2
11.Save the file with wq:
12.To check your configuration file type testparm
 #testparm
13.Create two samba users user1 and user2
 useradd user1
 useradd user2
14.Create smbpassword for both the users
 smbpasswd –a user1
 smbpasswd –a user2
15.Now you stop/start the samba services
 #service smb stop
 #service smb start
16.To see what is shared from your server through samba for a particular user
 #smbclient  -L server1 –U user1  or smbclient –L //192.168.0.1 –U user1
17.To see what is shared for a particular host
 #smbclient –L  mac2
18.Now, permanently make samba server on
 #chkconfig smb on

What cloud computing really means

Cloud computing is all the rage. "It's become the phrase du jour," says Gartner senior analyst Ben Pring, echoing many of his peers. The problem is that (as with Web 2.0) everyone seems to have a different definition.
As a metaphor for the Internet, "the cloud" is a familiar cliché, but when combined with "computing," the meaning gets bigger and fuzzier. Some analysts and vendors define cloud computing narrowly as an updated version of utility computing: basically virtual servers available over the Internet. Others go very broad, arguing anything you consume outside the firewall is "in the cloud," including conventional outsourcing.

[ Stay on top of the state of the cloud with InfoWorld's "Cloud Computing Deep Dive" special report. Download it today! | Also check out our "Private Cloud Deep Dive," our "Cloud Security Deep Dive," our "Cloud Storage Deep Dive," and our "Cloud Services Deep Dive." ]

Cloud computing comes into focus only when you think about what IT always needs: a way to increase capacity or add capabilities on the fly without investing in new infrastructure, training new personnel, or licensing new software. Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities.

Cloud computing is at an early stage, with a motley crew of providers large and small delivering a slew of cloud-based services, from full-blown applications to storage services to spam filtering. Yes, utility-style infrastructure providers are part of the mix, but so are SaaS (software as a service) providers such as Salesforce.com. Today, for the most part, IT must plug into cloud-based services individually, but cloud computing aggregators and integrators are already emerging.

InfoWorld talked to dozens of vendors, analysts, and IT customers to tease out the various components of cloud computing. Based on those discussions, here's a rough breakdown of what cloud computing is all about:

1. SaaSThis type of cloud computing delivers a single application through the browser to thousands of customers using a multitenant architecture. On the customer side, it means no upfront investment in servers or software licensing; on the provider side, with just one app to maintain, costs are low compared to conventional hosting. Salesforce.com is by far the best-known example among enterprise applications, but SaaS is also common for HR apps and has even worked its way up the food chain to ERP, with players such as Workday. And who could have predicted the sudden rise of SaaS "desktop" applications, such as Google Apps and Zoho Office?
2. Utility computingThe idea is not new, but this form of cloud computing is getting new life from Amazon.com, Sun, IBM, and others who now offer storage and virtual servers that IT can access on demand. Early enterprise adopters mainly use utility computing for supplemental, non-mission-critical needs, but one day, they may replace parts of the datacenter. Other providers offer solutions that help IT create virtual datacenters from commodity servers, such as 3Tera's AppLogic and Cohesive Flexible Technologies' Elastic Server on Demand. Liquid Computing's LiquidQ offers similar capabilities, enabling IT to stitch together memory, I/O, storage, and computational capacity as a virtualized resource pool available over the network.
3. Web services in the cloudClosely related to SaaS, Web service providers offer APIs that enable developers to exploit functionality over the Internet, rather than delivering full-blown applications. They range from providers offering discrete business services -- such as Strike Iron and Xignite -- to the full range of APIs offered by Google Maps, ADP payroll processing, the U.S. Postal Service, Bloomberg, and even conventional credit card processing services.
4. Platform as a serviceAnother SaaS variation, this form of cloud computing delivers development environments as a service. You build your own applications that run on the provider's infrastructure and are delivered to your users via the Internet from the provider's servers. Like Legos, these services are constrained by the vendor's design and capabilities, so you don't get complete freedom, but you do get predictability and pre-integration. Prime examples include Salesforce.com's Force.com, Coghead and the new Google App Engine. For extremely lightweight development, cloud-based mashup platforms abound, such as Yahoo Pipes or Dapper.net.
5. MSP (managed service providers)One of the oldest forms of cloud computing, a managed service is basically an application exposed to IT rather than to end-users, such as a virus scanning service for e-mail or an application monitoring service (which Mercury, among others, provides). Managed security services delivered by SecureWorks, IBM, and Verizon fall into this category, as do such cloud-based anti-spam services as Postini, recently acquired by Google. Other offerings include desktop management services, such as those offered by CenterBeam or Everdream.
6. Service commerce platformsA hybrid of SaaS and MSP, this cloud computing service offers a service hub that users interact with. They're most common in trading environments, such as expense management systems that allow users to order travel or secretarial services from a common platform that then coordinates the service delivery and pricing within the specifications set by the user. Think of it as an automated service bureau. Well-known examples include Rearden Commerce and Ariba.
7. Internet integrationThe integration of cloud-based services is in its early days. OpSource, which mainly concerns itself with serving SaaS providers, recently introduced the OpSource Services Bus, which employs in-the-cloud integration technology from a little startup called Boomi. SaaS provider Workday recently acquired another player in this space, CapeClear, an ESB (enterprise service bus) provider that was edging toward b-to-b integration. Way ahead of its time, Grand Central -- which wanted to be a universal "bus in the cloud" to connect SaaS providers and provide integrated solutions to customers -- flamed out in 2005.
Today, with such cloud-based interconnection seldom in evidence, cloud computing might be more accurately described as "sky computing," with many isolated clouds of services which IT customers must plug into individually. On the other hand, as virtualization and SOA permeate the enterprise, the idea of loosely coupled services running on an agile, scalable infrastructure should eventually make every enterprise a node in the cloud. It's a long-running trend with a far-out horizon. But among big metatrends, cloud computing is the hardest one to argue with in the long term.

Xen 4.4 Open Source Virtualization Targets ARM and Cloud

Enhanced ARM support and stronger scalability for cloud computing servers highlight the long list of new features in Xen 4.4, the open source virtualization hypervisor whose release the Linux Foundation has announced.
Xen offered some ARM support before, but it is much more comprehensive in the latest version. Now, the hypervisor supports all of the following ARM platforms: AppliedMicro’s X-Gene, the Arndale Board, Calxeda ECX-2000, TI OMAP5 and the Allwinner SunXi boards. It also features support for 64-bit guests on ARMv6 systems, as well as userspace tools for creating and managing virtual machines that are "64-bit ready" in ARM environments.
Xen 4.4 also introduces a new event channel implementation, developed by the XenServer team at Citrix (CTXS), that allows the hypervisor to run thousands of guests on a single bare-metal server. That enhancement, the developers say, will be important for driving continued evolution in the open source cloud by enabling more scalability and allowing administrators to take advantage of larger physical machines.
Meanwhile, Oracle (ORCL) has contributed a new virtual mode for Xen, called PVH, that is available in Xen 4.4 as a "functional preview." It provides paravirtualization support, allowing Xen to take advantage of some of the virtualization extensions available on host CPUs.
These are only the headlining updates in the new release, which also introduced performance enhancements for storage devices, better diagnostics and debugging and Spice protocol support to simplify the sharing of clipboards and other resources between guest and host machines.
In many ways, KVM, another open source hypervisor, remains the darling of the open source community, with its tight integration with the Linux kernel and strong support from the Linux Foundation through the Open Virtualization Alliance. But Xen remains an important contender in the virtualization world as well, and it enjoys support from the Linux Foundation as a collaborative project. With its sights set on ARM and low-power servers, Xen appears to be carving out a somewhat different niche to distinguish itself from KVM.

Researchers have documented an ongoing criminal operation infecting more than 10,000 Unix and Linux servers with malware that sends spam and redirects end users to malicious Web pages.
Windigo, as the attack campaign has been dubbed, has been active since 2011 and has compromised systems belonging to the Linux Foundation's kernel.org and the developers of the cPanel Web hosting control panel, according to a detailed report published Tuesday by researchers from antivirus provider Eset. During its 36-month run, Windigo has compromised more than 25,000 servers with robust malware that sends more than 35 million spam messages a day and exposes Windows-based Web visitors to drive-by malware attacks. It also feeds people running any type of computer banner ads for porn services.
The Eset researchers, who have been instrumental in uncovering similar campaigns compromising large numbers of servers running the nginx, Lighttpd, and Apache Web servers, said the latest campaign has the potential to inflict significant harm on the Internet at large. They explained:

The number of systems affected by Operation Windigo might seem small when compared with recent malware outbreaks where millions of desktops are infected. It is important to keep in mind that, in this case, each infected system is a server. These usually offer services to numerous users and are equipped with far more resources in terms of bandwidth, storage and computation power than normal personal computers. A denial of service attack or a spam-sending operation using one thousand servers is going to be far more effective than the same operation performed with the same number of desktop computers.

For more....

10,000 Linux servers hit by malware serving tsunami of spam and exploits

Step-by-step guide to installing Windows 8 Release

In this guide I will cover the installation of Microsoft Windows 8 Release Preview 64-bit from a installation image. The installation of 32-bit and 64-bit are the same as this guide. I will try to explain certain options and provide helpful hints along the way, so rather than just following the guide, you can understand the reasoning behind the decisions.

If there are any mistakes please draw my attention to them and I will correct as needed. I have tried to make this as simple as possible, whilst covering the vast majority of scenarios users will come across whilst installing this operating system.

Step 1:
Download the installation image for your chosen architecture. The image used in the creation of this guide is the 64-bit (x64) ISO.

Step 2:
Using your disc burning software, burn the .iso you downloaded to a DVD.

Step 3:
Before you go any further, ensure all important data is backed up in case of data loss on your drives. This guide assumes you have media backups of your hard drives and you are safe to proceed.

Warning: Installing another operating system without first ensuring you have backups of your current files and operating system is a big risk. If you have no data to lose or you’ve backed up important data, you’re ready to proceed. YOU are responsible if you lose data.

Disclaimer: It goes without saying, that neither me or TechSpot accept any liability or responsibility for any errors or damages made to your computer during, or after installing this operating system. It is up to the user to ensure proper backups are made of important documents and files.

Step 4:
Ensure you have a network cable connected, restart your computer, and boot from the DVD drive.

Step 5:
The DVD will begin to load up, and you'll be presented by the following screen as the installer starts.

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Step 6:
Once loaded you will see the following screen.

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Select your location, keyboard and regional language settings as required and click "next" to continue and you'll see the following box:

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Click "Install now" to continue with the installation.

Step 7:
You'll then be asked to provide the product key to activate Windows.

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Enter the product key as written in the screenshot above.
Once you have entered the product key, click "next" to continue to the next step.

Step 8:
Before you can proceed with the setup any further you're required to accept Microsoft's license terms, as below.

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Read the terms, and once you're happy, tick the "I accept the license terms" box, and click "next" to continue to the next step.

Step 9:
You will be greeted with the following screen.

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For the purposes of this guide, we'll assume you are performing a fresh installation of Windows 8 Release Preview. Therefore, this tutorial covers the "Custom" option which will install a fresh copy of Windows 8 Release Preview onto a clean hard drive, without backing up and restoring any existing files or settings.

The first option, "upgrade" will allow those running previous versions of Windows to upgrade to Windows 8 whilst keeping all files, settings and applications during the setup of the new operating system.

Step 10:
The setup will then continue and start the disk manager as below.

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Select the correct drive to use for the installation of Windows 8 Release Preview, and click "next" to continue. For those trying this in a Virtual Machine, 20-25GB of hard drive space is more than adequate.

Note: This step is the last point in which you can abort the installation without permanent data loss to drives. Please ensure you have working backups before proceeding further.

Step 11:
Windows setup will then begin to install Windows 8 Release Preview to the hard drive, and will work through several stages as detailed below.

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The installer may restart during the installation stage as it configures the computer to run the new operating system.

Step 12:
Once complete, it will reboot again and setup the computers devices and finalize the installation, as below.

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Once this stage has finished, you will be greeted with the following screen.

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Select your preferred colour scheme for Metro, and then name your computer. The PC name is used to identify the computer on local networks and ideally should be named so that other users your network can identify who the computer belongs to. Then click "next" to proceed.

Step 13:
You will then be greeted with the following window.

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At this point you can specify the final settings required in the configuration of your new Windows installation. You can either choose "use express settings" or click "customize" to change the express settings.

If you are unsure, it is best to choose the first option. The installer will then configure the final settings and move onto the next step.

Step 14:
The next step asks you if you wish to sign into your PC using a Windows Live account.

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Unlike previous versions of Windows, Microsoft's new operating system heavily integrates the Redmond-based firms Windows Live features, including messenger, contacts, calendar and mail.

Signing in using your Windows Live account also offers Windows 8 users additional benefits like the ability to download additional apps from the Windows Store and automatic synchronization of all your Windows 8 computers so they look and feel the same regardless of which one you're using.

Note: Your Windows Live ID also becomes your username for Windows 8 Release Preview, and uses your Windows Live ID password to log in.

Enter your Windows Live ID, and click "next" to continue.

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You will then be asked for your password for your Windows Live account. Click "next" to continue.

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The final step of integrating your Windows Live account with your new installation of Windows 8 Release Preview requires you to provide additional verification information. For those that have previously set this up, the fields will be completed already. Verify they are correct, or add the required information and click "next" to continue.

Step 15:
Windows 8 Release Preview will then complete its final configuration.

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Once complete, it will then boot into Windows for the first time, as below.

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Installation is now complete, and you can enjoy your new OS and begin exploring its features.