If not, copy-paste the below code to your websites .htaccess file.

RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?yourdomain.com/.*$ [NC]
RewriteRule ^.*\.(bmp|tif|gif|jpg|jpeg|jpe|png)$ – [F]

Haii.. Linux buddy,, you now. safe….  :D

 It makes sure that all processes in the system works fine

Rebuilding

It is done to optimize the kernel to suit our requirements as well as make it more secure from internet attacks

 Steps

1. Determining the current hardware 
 This is required during configuration process to enable hardwares that our new kernel has to support.
Commands used for the same are:

2. Download the Source
latest sources and its corresponding patches are always available fromhttp://www.kernel.org/pub/linux/kernel/
 As of today (Oct 21, 2008) the latest available source is linux-2.6.27.2.tar.gz and the patch is patch-2.6.27.2.gz

Apply the patches

Extract the source using tar -zxvf and patch using gunzip to /usr/src/ folder.

Now cd to linux-2.6.27.2 and apply the patch as shown below:

4. Configuration
 You may copy the current configuration by copying the file .config.

cp ../linux/.config config.old

 Begin the configuration by wiping out all previous configurations and resetting the source directory to a pristine state:

Run the configuration utility. Either of the below step can be used to run the configuration utility:

5. Start Build
Clean before the build:

 Start the build after cleaning process:

6. Build and install all the loadable modules

7. Copy the required files and generate initrd
 Copy the files over for the kernel itself

 If you come across an error like: “/dev/mapper/control: open failed: No such file or directory” , Run the following commands:

8. Configure Grub & enable failsafe
  Open grub.conf file
  Add the below code to the top of the kernel list:

  Set the default value to your working kernel. (NOTE: NOT NEW KERNEL)
  Now save and exit from grub.conf file and enter into grub mode by typing “grub” from bash prompt
  And set to boot from newly compiled kernel during next reboot:

 If your server is up, you are done with your new kernel. Open the file grub.conf and change the value of default to “0″

Congratulations! You are done with your new kernel.

echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

To Enable Ping:

echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

To log into “Server A” from “Server B” without using passwords. Users for both the server will be “root”

Process

 Login to “Server B” as root user and generate key for the root user. No need to enter any passphrase while generating this key.

ssh-keygen -t rsa

Once the key is generated, copy the contents of “Server B” /root/.ssh/id_rsa.pub to “Server A” /root/.ssh/authorized_keys file. Make sure that the permission of authorized_keys is 0600 and .ssh folder is 0700 .

Also make sure that you have the following lines in your /etc/ssh/sshd_config file: 
RSAAuthentication yes
PubkeyAuthentication yes

Finally restart your ssh service and try logging to your “Server B” from “Server A”:

/etc/init.d/sshd restart

ssh [Server_A_ip]

* Find all HTML files starting with letter ‘a’ in your current directory (Case sensitive):

find . -name a\*.html

Same as above but case insensitive search:

find . -iname a\*.html

Find files which are larger than 5 MB in size:

find . -size +5000k -type 

Here the ‘+’ in ‘+5000k’ indicates greater than and k is kilobytes. And the dot ‘.’ indicates the current directory. The -type option can take any of the following values:
f – file
d – directory
l – symbolic link
c – character
p – named pipe (FIFO)
s – socket
b – block device

* Find all empty files in your directory:

find . -size 0c -type f

… Which is all files with 0 bytes size. The option -size can take the following:
c – bytes
w – 2 byte words
k – kilo bytes
b – 512 byte blocks

* Find is very powerful in that you can combine it with other commands. For example, to find all empty files in the current directory and delete them, do the following:

find . -empty -maxdepth 1 -exec rm {} \;

 To search for a html file having the text ‘Web sites’ in it, you can combine find with grep as follows:

find . -type f -iname \*.html -exec grep -s “Web sites” {} \;

… the -s option in grep suppresses errors about non-existent or unreadable files. And {} is a placeholder for the files found. The semicolon ‘;’ is escaped using backslash so as not to be interpreted by bash shell.

Compress log files on an individual basis:

find /var -iname \*.log -exec bzip {} \;

Find all files which belong to user lal and change its ownership to ravi:

find / -user lal -exec chown ravi {} \;

xargs command cal also be used instead of the -exec option as follows:

find /var -iname \*.log | xargs bzip -

 Find all files which do not belong to any user:

find . -nouser

Find files which have permissions rwx for user and rw for group and others :

find . -perm 766

and then list them:

find . -perm 766 -exec ls -l {} \;

Find all directories with name music_files:

find -type d -iname \*music_files\* 

 find files of size between 700k and 1000k

find . \( -size +700k -and -size -1000k \)

How about getting a formatted output of the above command with the size of each file listed ?:

find . \( -size +700k -and -size -1000k \) -exec du -Hs {} \; 2>/dev/null

You can also limit your search by file system type. For example, to restrict search to files residing only in the NTFS and VFAT filesystem, do the following:

find / -maxdepth 2 \( -fstype vfat -or -fstype ntfs \) 2> /dev/null

If php-apache relationship is CGI, then php.ini file is used to disable safe_mode value

 If none of the above works, contact your hosting provider and ask them to disable safe_mode through the servers httpd.conf file. It can be done in your VirtualHost configuration inside httpd.conf file.

.htaccess Code

php_admin_value safe_mode Off [OR]
php_flag safe_mode Off

edit php.ini ( use this command to find php.ini file location – “php -i | grep php.in” ) 

safe_mode = Off

edit httpd.cof 

php_admin_value safe_mode Off

Verify your settings

 Create phpinfo page file  and put it on the document root and access the page to see if the defult value has been overrided with your defult value.

phpinfo sample. 

example 
vi  phpinfo.php

<?php
phpinfo();
?>

You may use register_globals keyword instead of safe_mode to change values of register_globals variable [off/on values are accepted]

Unless the ftp users are limited to their home directories, they will able to access all files & folders on the server .

How to

Below you may see how this can done to 3 of the ftp servers used in common.

Pro-ftpd

vsftpd

pure-ftpd

Pure-ftpd

vi  /etc/pure-ftpd.conf

And change the following line

ChrootEveryone=YES

pro-ftpd

vi /etc/proftpd.conf

DefaultRoot ~

Vsftpd

vi /etc/vsftpd.conf

Installation

Please follow the steps to install imagemagick

download latest version from source

ftp://ftp.imagemagick.org/pub/ImageMagick/ImageMagick.tar.gz

unpack the source

tar  zxvf  ImageMagick.tar.gz

Next configure and compile ImageMagick:

cd ImageMagick.6.?.?

./configure

make

Installing

make install

PerlMagick is an objected-oriented Perl interface to ImageMagick. Use the module to read, manipulate, or write an image or image sequence from within a Perl script. This makes it very suitable for Web CGI scripts. You must have ImageMagick 6.2.0 or above and Perl version 5.005_02 or greater installed on your system for either of these utilities to work.

cd PerlMagick

perl Makefile.PL
make
make install

 

verify your installation

/usr/local/bin/convert logo: logo.gif

Congratulations, now your ready to go..............

We need to add some simple scipts to activate this feature.By defult hylafax will not decode the attachments.So you need to edit /etc/hylafax/hyla.conf.

specify mime type directory location in /etc/hylafax/hyla.conf

add the following line

MIMEConverters: /var/spool/hylafax/mimetype

Then create the converting scripts under /var/spool/hylafax/mimetype

mkdir /var/spool/hylafax/mimetype

you need to create followin directories under /var/spool/hylafax/mimetype

mkdir application

mkdir image

mkdir text

the tree look like this

/var/spool/hylafax/mimetype/
/var/spool/hylafax/mimetype/application/pdf
/var/spool/hylafax/mimetype/application/ps
/var/spool/hylafax/mimetype/image/tiff

/var/spool/hylafax/mimetype/text/html

For msword type of files create msword under /var/spool/hylafax/mimetype/application/

cd /var/spool/hylafax/mimetype/application/

touch msword

chmod +x  msword

vi msword

add the following lines in msword script

#!/bin/bash
antiword $1
exit

For PDF type of files create pdf under /var/spool/hylafax/mimetype/application/

cd /var/spool/hylafax/mimetype/application/

touch pdf

chmod +x pdf

vi pdf

add the following lines in pdf script

#!/bin/sh
#/application/pdf
# convert PDF attachment to Postscript for HylaFAX to send
pdf2ps $1 -
# if you want to send multipage pdf attachments it is better to use “pdftops”
# use the line below instead of “pdf2ps $1 -”
# /usr/bin/pdftops $1 -

For postscript type of files create postscript under /var/spool/hylafax/mimetype/application/

cd /var/spool/hylafax/mimetype/application/

touch postscript

chmod +x postscript

vi postscript

add the following lines in postscript script

#!/bin/sh
#/application/pdf
# convert PDF attachment to Postscript for HylaFAX to send
pdf2ps $1 -
# if you want to send multipage pdf attachments it is better to use “pdftops”
# use the line below instead of “pdf2ps $1 -”
# /usr/bin/pdftops $1 -
mail:/var/spool/hylafax/mimetype/application #
mail:/var/spool/hylafax/mimetype/application # cat postscript
#!/bin/sh
#/application/ps
# convert PS attachment to Postscript for HylaFAX to send
echo $1

For PS attachment files create ps under /var/spool/hylafax/mimetype/application

cd /var/spool/hylafax/mimetype/application/

touch postscript

chmod +x postscript

vi postscript

add the following lines in ps script

#!/bin/sh
#/application/ps
# convert PS attachment to Postscript for HylaFAX to send
echo $1

For rtf attachement files create rtf under /var/spool/hylafax/mimetype/application

cd /var/spool/hylafax/mimetype/application/

touch rtf

chmod +x rtf

vi rtf

add the following lines in rtf

#!/bin/sh
#/application/rtf
# convert RTF attachment to Postscript for HylaFAX to send
/usr/bin/unrtf –html $1 | /usr/bin/html2ps

For jpeg attachment files create jpeg under /var/spool/hylafax/mimetype/image

cd /var/spool/hylafax/mimetype/image

touch image

chmod +x image

vi image

add the following lines in jpeg

#! /bin/sh
/usr/bin/jpeg2ps  $1
exit

For tiff attachment files create tiff under /var/spool/hylafax/mimetype/image

cd /var/spool/hylafax/mimetype/image

touch tiff

chmod +x tiff
vi tiff

Then add the following lines

#! /bin/sh
/usr/bin/jpeg2ps  $1
exit
mail:/var/spool/hylafax/mimetype/image # cat tiff
#!/bin/sh
#/image/tif
# convert TIF attachment to Postscript for HylaFAX to send
/usr/bin/tiff2ps $1
# if you want to send multipage tiff images, than you have to add the option “-a”
# for example:
#/usr/bin/tiff2ps -a $1

For HTML type  files create html under /var/spool/hylafax/mimetype/text

cd /var/spool/hylafax/mimetype/text

touch html

chmod +x html
vi html

then add the following lines.

#! /bin/sh
/usr/bin/html2ps   $1
exit

Integrating with MTA’s

cd /usr/src/hylafax-(source package)

cd faxmail

there you can see the files

mailfax.sh-sendmail

mailfax.sh-postfix

mailfax.sh-qmail

mailfax.sh-smail

do as per the files says.