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red hat linux

Redhat / CentOS / Fedora Linux Open Port

Q. I’ve Redhat Enterprise Linux 5 server with Iptabeles firewall enabled. By default it is only allowing port 22. How do I open port 80 / 143 / 110 on Linux? I've started all services but don't know how to open port using iptables.

A. By default iptables firewall stores its configuration at /etc/sysconfig/iptables file. You need to edit this file and add rules to open port number. This file only avilable under
Red Hat Enterprise Linux 3 / 4 / 5 and above
=> Old Red hat Linux version
=> CentOS 4 and above
=> Fedora Linux

Open port 80

Open flle /etc/sysconfig/iptables:
# vi /etc/sysconfig/iptables
Append rule as follows:
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
Save and close the file. Restart iptables:
# /etc/init.d/iptables restart

Open port 110

Append rule as follows:
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 110 -j ACCEPT

Open port 143

Append rule as follows:
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 143 -j ACCEPT

Restart iptables service

Type the following command:
# service iptables restart

Verify that port is open

Run following command:
netstat -tulpn | less
Make sure iptables is allowing port 80 / 110 / 143 connections:
iptables -L -n

Refer to iptables man page for more information about iptables usage and syntax:
man iptables

I have installed Red Hat enterprise Linux version 5.x server. Next, I added a brand new LAN card (NIC). I can see my second network card detected while booting the IBM server. How do I configure the network card from the command line?
[click to continue…]

PHP not connecting to a MySQL database server

Q. I have Apache Web server and MySQL configured. Everything works fine except I am not able to connect to a MySQL database server (I am able to connect mysql server with mysql client). So how do I configure or connect PHP scripts?

A. You need to install MySQL module for php4 or php5. Without php-mysql shared object or module, php scripts won't able to connect to MySQL database server.

Debian / Ubuntu Linux User

To install type the following command:
# apt-get install php4-mysql
if you are using PHP5, enter:
# apt-get install php5-mysql

RHEL <= 4 user

If you are using Red Hat Linux:
# up2date php-mysql

If you are using Fedora / CentOS / RHEL 5 Linux:
# yum install php-mysql
Restart apache to take effect. Now you will be able to connect MySQL via PHP scripts.
# service httpd restart