Call to undefined function: mysql_connect()

Solutions:

Solution 1)   Remove php5-mysql with “apt-get remove php5-mysql”  and install it again or

Solution 2)   Check your php.ini file to ensure it’s including the mysql.so library (extension=mysql.so)  or

Solution 3)   Type “dpkg-reconfigure php5-mysql” (For ubuntu and debian users)

Solaris and Linux Runlevel

Default Linux Run Level: Total 7 Run Level

RunLevel 0: Halt System – To shutdown the system
RunLevel 1: Single user mode
RunLevel 2: Basic multi user mode without NFS
RunLevel 3: Full multi user mode (text based)
RunLevel 4: unused
RunLevel 5: Multi user mode with Graphical User Interface
RunLevel 6: Reboot System

Default Solaris Run Level: Total 8 Run Level

RunLevel S: Single user state (useful for recovery)

RunLevel 0: Access Sun Firmware (ok> prompt)

RunLevel 1: System administrator mode

RunLevel 2: Multi-user w/o NFS

RunLevel 3: Multi-user with NFS

RunLevel 4: Unused

RunLevel 5: Completely shutdown the host (like performing a power-off)

RunLevel 6: Reboot but depend upon initdefault entry in /etc/inittab

Update system

Configure Services in CentOs5/RHEL5

1) List All services

2)  List Running services at Runlevel 3

3) Start service

4)      Stop service

5)   Start service on different RunLevel

6)  Restart services

7)  Add services

8 ) Remove Services

CentOS5/RHEL5 User Administration

1) Add User

2)      Delete user

3)      Modify user

4) Add Group

5) Delete group

6) Modify group

7) Add User to Group

Use useradd command to add new users to existing group (or create a new group and then add user). If group does not exist, create it. Syntax:

Syntax:

useradd -G {group-name1},{group-name2} username (for secondary group)

useradd -g {group-name} username (for primary group)

Automated Installation of DenyHost on RedHat/Fedora

#Script

#!/bin/bash

# This script installs Deny Host on RedHat(RHEL) or Fedora.

################################################################################

# This script comes with no warranty or guarantee. Please review the script

# before you run it to ensure that it will not cause adverse effects on your

# system.

#

# If you have any questions or comments, please e-mail: sanjaydalal4u@gmail.com

################################################################################

sudo echo

if [ -f /etc/init.d/denyhosts ]; then

echo Removing existing init scripts

sudo /etc/init.d/denyhosts stop

sudo rm -rf /etc/init.d/denyhosts

sudo chkconfig –remove denyhosts

echo ‘*********************’

echo

fi

if [ -d /usr/share/denyhosts/ ]; then

echo Removing existing installation

sudo rm -rf /usr/share/denyhosts

echo ‘*********************’

echo

fi

echo Installing ‘python’ and dependencies.

sudo yum -y install python

echo ‘*********************’

echo

cd /root

echo Downloading DenyHost

wget http://downloads.sourceforge.net/project/denyhosts/denyhosts/2.6/DenyHosts-2.6.tar.gz?use_mirror=biznetnetworks

echo ‘*********************’

echo

echo Unpacking DenyHost

#!/bin/bash

# This script installs Deny Host on RedHat(RHEL) or Fedora.

################################################################################

# This script comes with no warranty or guarantee. Please review the script

# before you run it to ensure that it will not cause adverse effects on your

# system.

# If you have any questions or comments, please e-mail: sanjaydalal4u@gmail.com

################################################################################

sudo echo

if [ -f /etc/init.d/denyhosts ]; then

echo Removing existing init scripts

sudo /etc/init.d/denyhosts stop

sudo rm -rf /etc/init.d/denyhosts

sudo chkconfig –remove denyhosts

echo ‘*********************’

echo

fi

if [ -d /usr/share/denyhosts/ ]; then

echo Removing existing installation

sudo rm -rf /usr/share/denyhosts

echo ‘*********************’

echo

fi

echo Installing ‘python’ and dependencies.

sudo yum -y install python

echo ‘*********************’

echo

cd /root

echo Downloading DenyHost

wget http://downloads.sourceforge.net/project/denyhosts/denyhosts/2.6/DenyHosts-2.6.tar.gz?use_mirror=biznetnetworks

echo ‘*********************’

echo

echo Unpacking DenyHost

tar -xzf DenyHosts-2.6.tar.gz

cd /root/DenyHosts-2.6

echo ‘*********************’

echo

echo Installing DenyHost

sudo python setup.py install

echo ‘*********************’

echo

cd /usr/share/denyhosts

echo Configuring DenyHost

sudo cp denyhosts.cfg-dist denyhosts.cfg

sudo sed -i.bak ’s/^\s*\(SECURE_LOG\s*=.*\)$/#\1/’ denyhosts.cfg

sudo sed -i.bak ’s/^\s*#\s*SECURE_LOG\s*=\s*\/var\/log\/secure/SECURE_LOG = \/var\/log\/secure/’ denyhosts.cfg

sudo sed -i.bak ’s/^\s*\(LOCK_FILE\s*=.*\)$/#\1/’ denyhosts.cfg

sudo sed -i.bak ’s/^\s*#\s*LOCK_FILE\s*=\s*\/var\/run\/denyhosts.pid/LOCK_FILE = \/var\/run\/denyhosts.pid/’ denyhosts.cfg

sudo sed -i.bak ’s/^\s*\(BLOCK_SERVICE\s*=.*\)$/#\1/’ denyhosts.cfg

sudo sed -i.bak ’s/^\s*#\s*BLOCK_SERVICE\s*=\s*ALL/BLOCK_SERVICE  = ALL/’ denyhosts.cfg

echo ‘*********************’

echo

echo Configuring executable

sudo cp daemon-control-dist daemon-control

sudo sed -i.bak ’s/^\(\s*DENYHOSTS_BIN\s*=\s\).*$/\1″\/usr\/bin\/denyhosts.py”/’ daemon-control

sudo sed -i.bak ’s/^\(\s*DENYHOSTS_LOCK\s*=\s\).*$/\1″\/var\/run\/denyhosts.pid”/’ daemon-control

sudo sed -i.bak ’s/^\(\s*DENYHOSTS_CFG\s*=\s\).*$/\1″\/usr\/share\/denyhosts\/denyhosts.cfg”/’ daemon-control

sudo chown root daemon-control

sudo chmod 700 daemon-control

echo ‘*********************’

echo

echo Adding ddclient to rc scripts

cd /etc/init.d

sudo ln -s /usr/share/denyhosts/daemon-control denyhosts

sudo chkconfig –add denyhosts

sudo chkconfig –level 35 denyhosts on

echo ‘*********************’

echo

How to Open 7zip Files Under Ubuntu

Step 1 : Install application

#sudo apt-get install p7zip

Step 2 : Exectute this command

#p7zip -d filename.7z

Setup SAMBA server on Ubuntu 9.04

Step 1: Installation

#apt-get install samba

Step 2: Configuration

Configuration file : /etc/samba/smb.conf

• Edit below section

Workgroup = EXAMPLE

…………

Security = user

• Create a new section at the bottom of the file /etc/samba/smb.conf

[Samba Share]

Comment= Samba  File Server Share

Path=/path to directory

Browsable = yes

Guest ok = yes

Read only = no

Create mask = 0755

Step 3: Create directory and change permissions

#mkdir /path to directoy

#chown  -R nobody:nobody /path to directory

Step 4 : Restart Samba service

#/etc/init.d/samba restart

Enjoy!!!!!!!!!!!!

Open ports using IPTABLES

If you want your machine to respond to requests initiated from elsewhere on the internet you need to open the required ports. You need to know below details first:

1. Service name you want to open up
2. Is it a tcp or udp service?
3. Port number(s) uses by service?

Example:

To enable ssh access to your box from anywhere on for Class A networks, you could use something like

iptables -A allowed -p tcp –dport 22 -s 10.2.0.0/16 -j ACCEPT
iptables -A allowed -p udp –dport 22 -s 10.2.0.0/16 -j ACCEPT

iptables -A allowed -p tcp –dport 22 -s 10.8.0.0/16 -j ACCEPT
iptables -A allowed -p udp –dport 22 -s 10.8.0.0/16 -j ACCEPT

This allows both udp and tcp traffic from either of the two class A networks to access port 22 on your machine.

Work with tcpwrappers hosts.deny and hosts.allow

You can use tcpwrappers to Block user,ip,daemon from outside or your inside newwork. For allow use host.allow file and to block use host.deny file.

Step 1. Use your favorite editor like vi.

Step 2. Type vi /etc/hosts.deny
Step 3. At the bottom line just type “ALL:ALL:deny” to restricted all of daemon process
Step 4. Save it.
Step 5. Open “/etc/hosts.allow” with vi editor
Step 6. At the buttom line “ALL some ip that you allow):allow” to allow anything from my IP address
Step 7. Save it.