I am not able to use WGET ?

cp /usr/bin/wget /usr/bin/mywget

chmod 751 /usr/bin/mywget

How to make empty file?

echo –n >filename

OR

cat > filename (then press Ctl+d. The file will be be empty)

How directly run webstat through IE ( i.e domainname.com/webstat)

cd /home/username/public_html

ln -s ../tmp/webalizer webstat

cd ..

chmod 755 tmp

cd tmp

chmod 755 webalizer

How to disable telnet access on server

Telnet should be disabled on all web servers, and you should use SSH. Telnet sends password in plain text passwords and usernames through logins, and ‘crackers/hackers’ can obtain these passwords easily as compared to SSH. TELNET server listens for incoming messages on port 23, and sends outgoing messages to port 23.

1. Login to your server through SSH as a root user.

2. open file
# vi /etc/xinetd.d/telnet

3. Look for the line: disable = no and replace with disable = yes

4. Now restart the inetd service:
#/etc/rc.d/init.d/xinetd restart

5. Turn off it through chkconfig as well because it can still start through that.
#/sbin/chkconfig telnet off

6. Scan your server to ensure port 23 is closed.
#nmap -sT -O localhost

Also run ps -aux | grep telnet and if you find anything other than “grep telnet” as result kill the process.

Difference between Linux and Windows

Linux is an open-source Operating System. People can change codes and add programs to Linux OS which will help use your computer better. Linux evolved as a reaction to the monopoly position of windows. you can't change any code for windows OS. You can't even see which processes do what and build your onw extension. Linux wants the programmers to extend and redesign it's OS. Linux user's can edit its OS and design new OS.

All flavors of Windows come from Microsoft. Linux come from different companies like LIndows , Lycoris, Red Hat, SuSe, Mandrake, Knopping, Slackware.

Linux is customizable but Windows is not. For example,NASlite is a version of Linux that runs off a single floppy disk and converts an old computer into a file server. This ultra small edition of Linux is capable of networking, file sharing and being a web server.

Linux is freely available for desktop or home use but Windows is expensive. For server use, Linux is cheap compared to Windows. Microsoft allows a single copy of Windows to be used on one computer. You can run Linux on any number of computers.

Linux has hign security. You have to log on to Linux with a userid and password. You can login as root or as normal user. The root has full previlage.

Linux has a reputation for fewer bugs than Windows.

Windows must boot from a primary partition. Linux can boot from either a primary partition or a logical partition inside an extended partition. Windows must boot from the first hard disk. Linux can boot from any hard disk in the computer.

Windows uses a hidden file for its swap file. Typically this file resides in the same partition as the OS (advanced users can opt to put the file in another partition). Linux uses a dedicated partition for its swap file.

Windows separates directories with a back slash while Linux uses a normal forward slash.

Windows file names are not case sensitive. Linux file names are. For example "abc" and "aBC" are different files in Linux, whereas in Windows it would refer to the same file.

Windows and Linux have different concepts for their file hierarchy. Windows uses a volume-based file hierarchy while Linux uses a unified scheme. Windows uses letters of the alphabet to represent different devices and different hard disk partitions. eg: c: , d: , e: etc.. while in linux " / " is the main directory.

Linux and windows support the concept of hidden files. In linux hidden files begin with " . ", eg: .filename

In Linux each user will have a home directory and all his files will be save under it while in windows the user saves his files anywhere in the drive. This makes difficult to have backup for his contents. In Linux its easy to have backup's.

What is Digg?

Digg is a popular social bookmarking and content discovery website. Although site management and maintenance is done the website’s paid staff, everything on digg is submitted by the digg user community. These submissions are subject to peer review and are voted upon by other site visitors. The stories receiving enough diggs is posted on the websites front page, for the millions of digg visitors to see. According to Alexa, Digg is one of the most popular websites on the internet, reaching 1 out of every 100 internet users daily.

How to submit stories?

Submitting stories to digg is very easy. To submit stories you have to be a registered member of the digg, once you have registered and signed in, just click on the option submit story and then enter the URL of the story which you would like to submit. Then enter the title of the story with a short description and select the proper category for the story. You are only allowed to digg only original story and not any duplicate entry.

What can you do as a digg user?

Every digg user can digg (help promote), bury (help remove spam), and comment on stories. You can even digg and bury comments you like or dislike. Digg also allows you to track your friends’ activity throughout the site.

/Var FULL

Please impliment the following commands when your /var goes full :

Mentanance Policy
echo > /var/log/exim_mainlogecho > /var/log/exim_rejectlogecho > /var/log/maillogecho > /var/log/messagesecho > /var/log/messages.1echo > /var/log/messages.2echo > /var/log/messages.3echo > /var/log/messages.4echo > /var/log/lastlogecho > /var/log/maillogecho > /var/log/maillog.1echo > /var/log/maillog.2echo > /var/log/maillog.3echo> /var/log/secureecho> /var/log/secure.1echo> /var/log/secure.2echo> /var/log/secure.3echo> /var/log/secure.4echo > /usr/local/apache/logs/access_logecho > /usr/local/apache/logs/suexec_logecho > /usr/local/apache/logs/error_logecho > /usr/local/cpanel/logs/access_logecho > /usr/local/cpanel/logs/error_logecho > /var/log/exim_mainlog.1echo > /usr/local/cpanel/3rdparty/mailman/logs/locksecho > /var/log/cron.2echo > /var/log/chkservd.logecho > /var/log/cron.4echo > /var/log/exim_paniclog.1echo > /var/log/exim_rejectlog.1echo > /var/log/exim_paniclog

Also please check the email queue with the command exim -bpc

Further also try to delete the directory /scan which is under /var/spool/exim

Open DNS Servers

vi /etc/named.conf

Before the line that says “directory /var/named”; (it could be /var, /var/named, etc)
Put:
recursion no;

service named restart

Make sure you can ping yahoo.com and google.com afterwards.

Lame Server Resolve

service named stop

vi /etc/named.conf

add the three lines at the top

logging {

category lame-servers { null; };

};

service named restart

Using RPM

Installing software (rpm -i)
rpm -ivh package.rpm

Uninstalling software (rpm -e)
rpm -e software name

Updating packages (rpm -U)

Note :: This will uninstall and install the new package avoiding this annoying messages. It is also usual to install packages with –U flag in this way:

rpm -Uvh software.rpm

Lost Mysql root password ?

Few Simple steps to change your mysql root password.

service mysql stop

wait until MySQL shuts down. Then run

mysqld_safe –skip-grant-tables &

then you will be able to login as root with no password.

mysql -uroot mysql

In MySQL command line prompt issue the following command:

UPDATE user SET password=PASSWORD(”abcd”) WHERE user=”root”;
FLUSH PRIVILEGES;

At this time your root password is reset to “abcd” and MySQL will now
know the privileges and you’ll be able to login with your new password:

mysql -uroot -pabcd mysql

How to enable/disable PING

To Enable PING on the server

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

To Disable PING on the server

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

Missing DNS zone ?

If you are facing issue related to missing DNS zone with cpanel update do the following:

/scripts/perlinstaller Compress::Raw::Zlib
/scripts/perlinstaller –force Scalar::Util

This should fix the issue.

How to Set wildcard DNS

Edit the httpd.conf and add the line in virtual host of domain.

ServerAlias *.domain.com www.*.domain.com

restart httpd/apache service.

Now edit the DNS file or db file of domain and add the line as

*.domain.com. 14400 IN A IP of server
www.*.domain.com. 14400 IN A IP of server

restart named service

To turn off register globals for a particular user

Put the code in .htaccess
php_flag register_globals off

To view the .html first instead of .php

Add the code in .htaceess as DirectoryIndex index.html

How To use Yum

• To seach for a application

Yum will search all your enabled repos and tell you where you can obtain the package from

yum search application_name

• Yum can list all available packages from your enabled repos and tell you where you can obtain the package from:

yum list available

• To find out more info about some package

yum info application_name

• Installing applications

Inastalling is as easy as

yum install application_name

• Listing rpms

yum can list installed rpms for you from the repos you have enabled

yum list extras

• Removing rpms

Yum can remove a application and the dependenciesit installed with tat application. it will not remove depenencies if another application installed needs them.

yum remove application_name

• Updating the system

Yum can update the system for you with out user interact if you want it to.

yum update

• Not sure if you have upates?

yum check-update

• Local install

downloaded a rpm and cannot install it with rpm because of dependencies?

yum localinstall /path/to/the/rpm

How to increase file limit

Get current limit:

ulimit -n

cat /proc/sys/fs/file-nr

The default limit is 1024.

Get current number of open file descriptors:

lsof [-p pid] | wc -l

Increase the limit:

Edit /etc/security/limits.conf:

username hard nofile 32768




Send Email from a PHP Script Using SMTP Authentication

To connect to an outgoing SMTP server from a PHP script using SMTP authentication and send an email:

Adapt the example below for your needs. Make sure you change the following variables at least:
* from: the email address from which you want the message to be sent.
* to: the recipient's email address and name.
* host: your outgoing SMTP server name.
* username: the SMTP user name (typically the same as the user name used to retrieve mail).
* password: the password for SMTP authentication.
------------------------------------------------------------------------------------------------
require_once "Mail.php";

$from = "Bill Sender ";
$to = "Ninad Recipient ";
$subject = "Hi!";
$body = "Hi,\n\nHow are you?";

$host = "mail.example.com";
$username = "smtp_username";
$password = "smtp_password";

$headers = array ('From' => $from,
'To' => $to,
'Subject' => $subject);
$smtp = Mail::factory('smtp',
array ('host' => $host,
'auth' => true,
'username' => $username,
'password' => $password));

$mail = $smtp->send($to, $headers, $body);

if (PEAR::isError($mail)) {
echo("

" . $mail->getMessage() . "

");
} else {
echo("

Message successfully sent!

");
}
?>

-- Dhananjay Sonawane

Cron to delete mails from Inbox

Cron to delete mails from Inbox

Here is the syntax for deleting all email in the inbox of the default email address for a website:

echo -n > /home/youraccount/mail/inbox

-- Dhananjay Sonawane