My IT Blog

The Virtual Switch What really sets Hyper-V apart from Microsoft’s other virtualization products is that virtual machines perform much better because they can communicate with the server’s hardware directly rather than having to pass hardware requests through the host operating system (although there are some exceptions to this). Of course you can’t just bombard a network adapter with simultaneous traffic from multiple virtual machines. There has to be a way of managing the traffic. To get around this problem, Microsoft has introduced the concept of the virtual switch. To understand how this is possible, you have to realize that Hyper-V is not a Windows Server 2008 add-on, but rather is a part of the operating system. When you install the Hyper-V role, the hyper visor is placed “underneath” the Windows 2008 operating system. The existing operating system (known as the host operating system) is placed into something called the parent partition, and each guest operating sys

Installing a Virtual Operating System Open Server Manager and then navigate through the console tree to Roles -> Hyper-V -> Microsoft Hyper-V Server. If this is the first time that you have used Hyper-V, then you will be prompted to accept Hyper-V License Agreement. Once you accept the license agreement, the various Hyper-V options will be made available to you. The first thing that you must do is to click on the Connect to Server link, located in the Actions pane. When you do, you will be prompted to select the computer that you want to connect to. Choose the Local Computer option, and click OK. You will now see the screen shown in Figure A. This is the main screen that you will use for managing virtual machines. Creating a New Virtual Server To create a new virtual server, click the New -> Virtual Machine options found in the Actions pane. When you do, Windows will launch the New Virtual Machine Wizard. The wizard’s initial screen explai

Perform a Clean Installation The first thing that I recommend doing is to perform a clean installation of Windows Server 2008. Server virtualization is extremely resource intensive, far more so than most other server applications, so I recommend using a clean Windows installation on a dedicated server. Installing the Hyper-V Role Now, log in using an account with local administrative privileges, and then open the Server manager. In case you aren’t familiar with the Server Manager, it’s the new tool that acts as a centralized management utility for Windows Server 2008. You can access it by entering the ServerManager.msc command at the server’s Run prompt. When Server Manager opens, right click on the Roles container, and then choose the Add Roles command from the resulting shortcut menu. Windows will now launch the Add Roles Wizard. Click Next to bypass the wizard’s Welcome screen and then you should see a screen similar to the one shown in Figure A, asking you which roles y

Is your network cable plugged in? (physical) Is there a link light on the Ethernet switch and Ethernet NIC? (data-link) Do you have an IP address? (network) Can you ping your default gateway? (network, testing LAN IP connectivity) Do you have DNS server information? Can you ping your DNS server? (network, testing IP connectivity) Do you have a firewall configured? (network on up to application) Can you ping the host you are trying to get to by name? (application, DNS and network WAN IP connectivity) What format is the graphic in? Do you have a viewer for that format? (presentation) Can your web browser open up another website? (basic application troubleshooting) It may turn out that the graphic they were trying to bring up was a .TIFF file and they didn’t have a decoder for that type of file. Thus, this would have been a presentation error issue as the presentation layer deals with formats of graphics & files, as well as compression and encryption.

Open a terminal and type sudo su Type fdisk -l (note which partition contains the NTFS file system) Type mkdir /media/windows (This directory is where we will access the partition) Type mount /dev/hdx1 /media/windows/ -t ntfs -o nls=utf8,umask=0222 Type cd /media/windows (Moves us to the windows directory) Type ls to list the files on the NTFS partition Notes: Alternately, you can navigate to the media/windows directory outside of terminal to view the files. To unmount the Windows NTFS partiton, from the terminal simply type umount /media/windows/

The Open System Interconnection Reference Model (OSI) is a seven layer model that was developed as part of the effort to standardize networking that was started in the late 1970's as part of the Open Systems Interconnection (OSI) initiative. The Seven Layers of the OSI Model The Physical Layer defines the electrical and physical properties and the operating specifications for the devices and media in use. The main job of the Physical Layer is the physical "connection" or attachment of given media and how it is configured (e.g. Token Ring cable, size of cable used, termination in place etc.). In some instances, there may be secondary responsibilities of this layer depending on the device for things such as flow control, modulation/demodulation and so forth. The protocol data unit in use at this level of the OSI model is referred to as a "bit." The Data Link Layer provides the practical means to transfer data between network nodes as its main job is to transfe

An ISO image is an archive file (disk image) of an optical disc using a conventional ISO (International Organization for Standardization) format. ISO image files typically have a file extension of .ISO. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660. You can mount an ISO images via the loop device under Linux. It is possible to specify transfer functions (for encryption/decryption or other purposes) using loop device. But, how do you mount an ISO image under Linux? You need to use mount command as follows: Procedure to mount ISO images under Linux 1) You must login as a root user, if not root user then switch to root user using following command: $ su - 2) Create the directory i.e. mount point: # mkdir -p /mnt/disk 3) Use mount command as follows to mount iso file called disk1.iso: # mount -o loop disk1.iso /mnt/disk 4) Change dire

The first, and probably most important step, is to put down this row of values: 128 64 32 16 8 4 2 1 In order to remember these values start with the number 1, go from right to left, and double that number seven times. For example, start with 1 on the right side. For your next number, double the 1 (1 x 2 = 2). So, 2 is your next number (remembering to go from right to left). For your third number, double the 2 (2 x 2 = 4); to continue the sequence, double the 4 (4 x 2 = 8). Repeat this process until you’ve doubled your original number, seven times. The key to this is that every single one of the values we put in that row are going to have either number 1 or number 0 assigned to it. To convert the IP address we will take that string of numbers and start from left to right this time. For each value we ask this question: “Can I subtract this value from the decimal remaining?” If the answer is “NO” then you put a “0” under the binary value, and if the answer is “Y

ODR is used to allow hub routers to accept prefix information, distributed via Cisco Discovery Protocol (CDP) , from spoke routers. On the hub router, enter this command router odr Also, routes can be controlled with a distribute-list: distribute-list 10 in distribute-list 20 out assuming the referenced ACLs exist, otheriwse no routes are accepted or sent. Since the prefix updates are carried on CDP, ODR updates can be controlled, in true sledgehammer fashion, by disabling CDP on an interface:interface serial 0/0 no cdp enable For ODR to work properly, all dynamic routing protocols need to be disabled on the spoke routers.

If you need to get a quick list of running processes on your computer or another computer on your network, you can use the Windows Instrumentation command-line interface (WMIC) to quickly generate this. You can even generate a text file so you can print the list if need be. This Tech-Recipe applies to Windows XP Professional, Windows Vista, Windows Server 2003 and Windows Server 2008. 1. Open a command prompt. 2. Execute the following command: wmic process get description,executablepath To list the processes on another computer, execute the following command: wmic /node: process get description,executablepath Where computer name is the name of the desired computer. to generate a textfile, execute the following (make sure to change the output path to your liking): Your computer: wmic /output:d:\process.txt process get description,executablepath Another computer: wmic /node: /output:d:\process.txt process get description,executablepath Your results will look somethi

IGRP is a proprietary routing protocol designed by Cisco and can only be used in a homogeneous network of Cisco routers. IGRP is a distance-vector protocol that considers delay, bandwidth and other optional parameters to determine the best path. IGRP uses an autonomous system number parameter in the configuration. All routers with the same autonomous system number will share router advertisements and participate. This number is arbitrary but must be the same on all routers within the autonomous system. To configure a router to participate in IGRP routing within autonomous system 5 and advertise routing information about the 192.168.200.0 network, use: conf t router igrp 5 network 192.168.200.0