Archive for September, 2007

Who links to me

I wrote this simple online tool to find the external links to any web site, who and how many web sites in internet have links to any page of your web site or blog.

It uses a simple Google query applying basic Google operands knowledge to find sites with links to you(or backlinks or external links).

It doesn’t use the Google operator “link:” because, for example, “link:goohackle.com” returns only the links to “goohackle.com” home, if exists a link to another web page of goohackle.com, with this google operator you don’t gonna find it.

Then it returns the number of web sites with links to yours and the list of URLs who have links to your site.

I found useful for webmasters to get a measure of the popularity of your web site in internet and know who links to your web site or blog, to know the sites that link to yours.

You can use the online SEO tool here: Who links to me (GooLinks)

or go to SEO Tools section and take a look at my other web tools.

You can read how born this tool here: Error in Google Webmaster Tools

Online keyword popularity tool gives interesting results

I was testing the Web 2.0 technologies and I wrote a tool using Ajax and WebServices to get the popularity of any keyword in the web using the Google search engine results.

Google search amount of results

This can be very useful for webmasters to see the amount of competency who exists in the web for some keyword or phrase and perform a better SEO.

Also, it’s very interesting the results obtained for some words compared with others.

You can use it here: Keyword Popularity Tool

I’m working in a couple of other interesting tools related to Google SEO, the web and analysis about that… when I have time I’m gonna publish here…

How to create a portable encrypted file system on a loop file

Here I’m going to explain how to create an encrypted file system over a loop file. I also have a encrypted filesystem on a LVM partition but having them on a file has advantages like the capacity of copy the encrypted file in another PC and mount the file system there ( a portable encrypted file system ) or when you are, for example, in a server and you can’t create a new partition.

I do this with LUKS (Linux Unified Key Setup).

This “how to” is for Debian or Ubuntu but if you have another GNU/Linux distribution, it shouldn’t be too different, just install the packages like you always do.

First of all, use apt to install these packages:

apt-get install lvm2 cryptsetup e2fsprogs

Now let’s create, for example, a 500MB file:

dd if=/dev/zero of=/home/you/cryptfile bs=1M count=500

Asociate it with a loop device:

losetup /dev/loop0 /home/you/cryptfile

(if you have /dev/loop0 in use, just use another, like /dev/loop1, /dev/loop2, …)

Fill the file with random data:

badblocks -s -w -t random -v /dev/loop0

Using badblocks is better than create the file from /dev/urandom.
If you haven’t loaded the kernel module for the encryption you want, load them:

modprobe blowfish

When I write this, the default encryption algorithm was AES (if you prefer this use “modprobe aes”).

Create the encrypted file system asociated with the loop device:

cryptsetup -y luksFormat -c blowfish -s 256 /dev/loop0
cryptsetup luksOpen /dev/loop0 crypt_fun
mkfs.ext3 -j /dev/mapper/crypt_fun
e2fsck -f /dev/mapper/crypt_fun

In this case I create a ext3 file system, you can choose any other.

Also you can use another encryption algorithm with another options.

Try “man mkfs.ext3” and “man cryptsetup” to see different parameters and options.

Create a folder to mount the encrypted file system:

mkdir /media/fun

I made a couple of scripts to mount and unmount the file system:

mountCrypt.sh:

………………………………………

#! /bin/sh

(losetup /dev/loop0 /home/you/cryptfile || echo) && (cryptsetup luksOpen /dev/loop0 crypt_fun && mount /dev/mapper/crypt_fun /media/fun)
………………………………………

umountCrypt.sh:

………………………………………

#! /bin/sh

umount /media/fun && cryptsetup luksClose crypt_fun && losetup -d /dev/loop0
………………………………………
And that’s all, you have your portable encrypted file system ready!