Free: Namebench DNS Benchmarking Tool

March 17th, 2010 by Luis Ventura No comments »

It’s common practice to use the DNS provided by whoever your ISP is to resolve names on the Internet, but in some cases the ISP’s fail optimize or maintain their DNS server(allocate resources) resulting in poor performance.

Fortunately, a large number of alternative public DNS providers exists, the question is ‘Which one do I use ?‘. The answer to this question can be provided by Namebench a free and open source DNS benchmarking tool.

Namebech does not measure long term reliability.

Description from the Namebech home page

Try out namebench. It hunts down the fastest DNS servers available for your computer to use. namebench runs a fair and thorough benchmark using your web browser history, tcpdump output, or standardized datasets in order to provide an individualized recommendation. namebench is completely free and does not modify your system in any way. This project began as a 20% project at Google.

The whole DNS benchmarking test will be done for you automatically, actually all the user has to do is Download > Extract > Run Namebench and click on Start Benchmark . Wait four to five minutes for the test to be completed, when done Namebench will present you with the results by opening a window on your browser.

Hopefully, the results will help you make an informed decision on whether you should change DNS provider at all.

Namebench Home Page http://code.google.com/p/namebench/

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Test for errors in memory with Memtest86+

March 5th, 2010 by Luis Ventura No comments »

Memtest86+ is a easy to use memory diagnostics tool design to test and stress the systems Random Access Memory for errors and report any findings to the user.

Faulty memory can render a system unstable, incapable of booting at all, or even worse in possible data corruption. That’s why it’s good practice to use Memtest86+ or other tools with the same purpose every time new memory is acquired, better to spend a few minutes checking for errors than encounter errors at a later time.

Fortunately, Memtest86+ is an easy to use tool and the whole process happens automatically.

How do we use it ?

First of all you will need to visit the Memtest86+ home page and download the pre-compiled bootable ISO file. My preference is for the .zip ISO.

http://www.memtest.org

Note: I expect Nix* users to already have the knowledge of how to burn an ISO, meaning this tutorial will mainly focus on burning the ISO from Windows.

After the ISO is completely downloaded you will need to burn it to either a CD or DVD. Windows 7 has the capability to burn ISOs, if you have Windows XP I recommend you download ImgBurn which is a free burning application.

Note: older machines may not have a DVD drive.

How to burn an ISO on Windows 7

Open the directory where Memtest86+ resides and right click on the ISO application, now click on Burn disc image this will start a new window.

You can see in this window both the ISO and optical media are ready. Click on Burn to start the burning process. After it’s done the CD/DVD will be ejected.

How to Burn an ISO on Windows XP

After you are done downloading and installing ImgBurn you can start burning the ISO.

Since ImgBurn will integrate in to Windows you can just right click on the ISO and select Burn using ImgBurn.

A new window will automatically open, this window will prepare both the ISO and CD/DVD all you have to is click on the Write button which is located at the bottom of the window.

How do we start Memtest86+ ?

Once the ISO has been burned in to the media you will need to restart the computer and access the BIOS to set it to boot from CD/DVD media. The steps may change depending on the manufacturer, in some you may need to press F2, F10,or F12.

After you access the BIOS head over to the Boot configuration and set it to boot from CD-ROM/DVD-ROM Drive. Save the changes to the BIOS and exit, which will cause the system to restart.

Instead of booting from the hard drive the system will start from the CD/DVD Drive, since our CD/DVD containing Memtest86+ is inside the drive it will be automatically booted from. Here is the beauty of Memtest86+, you have to do nothing else just let the diagnosis tool run. Any errors will be reported on Errors column located in the middle of the screen.

Memtest86+ is simple tool you should keep around it may come in handy at a later time or whenever you buy new memory.

Memtest86+ Home Page

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Checksum a directory with md5deep

February 28th, 2010 by Luis Ventura No comments »

md5deep checksums

File integrity is no joke and system administrator know this is a problem that can result in unnecessary support tickets. If the users can be provided with the hash of a working document it can help narrow down the amount of variables. The problem administrators face is that unlike users, administrator have to manage servers with hundreds of thousands of files in each directory that have to be hashed. This lends it self to a few problems : hashing file by file is out of the question and a waste of time, which means we are left to find a solution that can work on a recursive manner.

Recursive operation – md5deep is able to recursive examine an entire directory tree. That is, compute the MD5 for every file in a directory and for every file in every subdirectory.

On the Windows platform you can use md5deep which is cross platform, works perfectly on Windows and best of all can handle a large number of files without breaking a sweat. It will literally create a checksum for all the files on the directory where md5deep is being used, the results are then exported to a single file where they can be used for verification at a later time.

md5deep is a software package used in the computer security, system administration and computer forensics communities for purposes of running large numbers of files through any of several different cryptographic digests.
Source: Wikipedia http://en.wikipedia.org/wiki/Md5deep

md5deep is managed from the command line, however it’s very easy to use considering it will be in charge of creating checksums for a large number of individual files.

How do we use it ?

md5deep example

First of all you can download md5deep from SourceForge.net.

After you download md5deep I recommend you move the executable to the C:\Windows directory for easy access from the command prompt.

For this tutorial I will be hashing a single directory. Start by opening the command prompt :

Start > Accessories > Command Prompt

On the Command Prompt type :

md5deep -rel "test_directory" > results_file.md5

Explanation of the command

  • r = recursive operation
  • e = compute estimated time remaining for file name
  • l = print relative paths for file name
  • “test_directory” = this points md5deep to the directory you wish to checksum
  • > results_file.md5 = is the file where all the results will be written to, you can name it whatever you want.

After md5deep is done you can open results_file.md5 to view and analyze the results.

Conclusion

md5deep is a simple tool that should be part of your arsenal, it might come in handy at a later time. Keep in mind that md5deep like tools will always require processing power, so try to use it during the light hours of the day.

md5deep Home page
Md5deep manual

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Iperf on Windows

February 15th, 2010 by Luis Ventura No comments »

Iperf is a neat little tool with the simple goal of helping administrator measure network performance and can measure both TCP and UDP performance on a network. Iperf is cross platform software and open source.

You can Download Iperf from noc.ucf.edu/Tools/Iperf/

We will be making use of the command line, do not fear the command line Iperf is a simple tool to use.

Let’s say I want to test the available bandwidth between a server(Windows Server 2008) and a client workstation(Windows 7). Iperf will try to move as much data as possible using the available link in order to conduct the test.

iperf-server-client-windows

Instructions

Download the Iperf executable and place the file on any directory you wish, my web browser(Firefox) places all downloaded files on the Download directory which where I will be executing Iperf.

Note:You will need to open port 5001 on the Iperf server.

Server Set Up

Go to Start > All Programs > Accessories > Command Prompt

command-prompt

With the command line prompt open type

cd Dowloads

or the location where the Iperf executable resides.

cd-download

Now that you are in the same directory as Iperf type

iperf -s

to start the Iperf server. If you look at the screen Iperf listens on port 5001 you may have to open port 5001 on your firewall.

iperf-server

Client Set Up

Imitating the steps above execute Iperf in the same manner, but this time we are going to give the Iperf client different instructions. On the Iperf client command line type

iperf -c 192.168.1.51

. This will be our client and we are telling Iperf the server is located at 192.168.1.51.

iperf-c

Give Iperf some time to test the connection after the test is done Iperf will present the results.

iperf-test-done

The results are easy to understand Iperf managed to transfer 113 Mbytes at 94.5 Mbits/s, now the results will changed when used on a busy network which is where Iperf will reveal the real available bandwidth on the network.

Also

My previous Iperf on Linux post

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