Tag Archives: Linux

Linux, Virtualization, VMware

Linux P2V CentOS 4/5/6 VMware Converter

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Recently I have been working on a project that had quite a few physical Linux servers, mainly of the the CentOS distribution. I have done the odd one here and there in the past but never really documented the process and with me attempting to update my blog more frequently what better place to document it.

First I will give a brief overview of the process then will detail the how-to. This post is for physical to virtual (P2V), I did have to tackle a few virtual to virtual (V2V) that were based on KVM to VMware which I will also document.

Overview

The version of Converter used during this project was 5.5.0 build 1362012 and CentOS versions 4.9, 5.1 and 6.5 x64. The sole use of converter may work on your combination of Converter, ESX and CentOS but in my case I had to create a new initial RAM disk as the converted VM would kernel panic due to disk configuration changes.

  1. Document kernel version
  2. Use VMware Converter to convert machine
  3. Create a new initial RAM disk
  4. Configure Network Connection
  5. Install VMware Tools

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Diary Entry

How to securely erase the hard disk in Linux

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How to securely erase the hard disk before selling ones computer

There are times when the news sites are abuzz with sensational news items. I am speaking of those news items which tempts one to pitch in and have his/her say come what may. And the news of someone who bought a laptop on ebay only to find it defective and how he took revenge on the seller by posting all the personal data on the hard disk on a website is by now a legend.

Now it is hard to decide who is in the right here – the person who published the private data on the website (for all you know, the laptop in question could have been damaged in transit) or the seller who is now the talk of the town, whose life is being dissected. There is no way to know. But that is besides the point. The truth is that it is scary to realize that it is next to impossible to delete all the data that one stores on ones storage media without completely destroying it. Because, with the right tools anybody can retrieve even deleted data.

So what can be done to alleviate the situation ? If you are using GNU/Linux or any other UNIX, then you have a tool called shred which can be used to wipe all the data from the hard disk. Here is how it works. Suppose I want to erase all the data on my hard disk, then I boot using a LiveCD like Knoppix and open a shell and type the following command:

# shred -vfz -n 100 /dev/hda

Here /dev/hda is my whole hard disk. And I am asking shred to make (-n) 100 passes by overwriting the entire hard disk with (-z) zeros. And shred program (-f) forces the write by changing the permissions wherever necessary.

Another GPLed tool (though not specifically related to Linux) which is quite popular is Darik’s Boot and Nuke (DBAN) which also does a swell job of wiping ones hard disk.

It is claimed that experts in the field of retrieving data can still get some data from a hard disk that has been wiped in the above manner. But atleast lesser mortals who buy second hand laptops and computers will find it beyond their means to lay their hands on the data.

All about Linux: How to securely erase the hard disk before selling ones computer

Diary Entry

Getting Your Site Listed – Diary Entry – 19th December 2007

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Today I have been looking into getting my website crawled by search engine bots and went straight to Google as you do to start submitting. In the process I came across a Webmaster Help Center Article which gave some good advise so thought I’d share, here a little quote.

When your site is ready:

* Have other relevant sites link to yours.
* Submit it to Google at http://www.google.com/addurl.html.
* Submit a Sitemap as part of our Google webmaster tools. Google uses your Sitemap to learn about the structure of your site and to increase our coverage of your webpages.
* Make sure all the sites that should know about your pages are aware your site is online.
* Submit your site to relevant directories such as the Open Directory Project and Yahoo!, as well as to other industry-specific expert sites.

Technical guidelines

* Use a text browser such as Lynx to examine your site, because most search engine spiders see your site much as Lynx would. If fancy features such as JavaScript, cookies, session IDs, frames, DHTML, or Flash keep you from seeing all of your site in a text browser, then search engine spiders may have trouble crawling your site.

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I saw the mention of Lynx (Text Browser) which I have used before as I am a total fan of the Back Track Project (An Security PenTest Live CD).

As I have a few sites I wanted to install Lynx on my super sweet Mac Book (Love both PC and Mac), typed it into Google and there it is on apples site.

Download Lynx for Mac

Once installed (all of 15 secs) I opened up Terminal typed lynx www.ezrahill.co.uk and it looked sweet. All as is so the bots should pick me up.

Lynx Text Browser

Quite a bit more to go over and quite a few more submissions to do to get listed in all of the big search engines. Here are a few links were you will wanna submit your site.

Add URL to Google
Submit to Yahoo
Open Directory Project