How to enable Port Forwarding in Iptables

What is Port Forwarding

Port forwarding allows remote computers, for example, computers on the Internet, to connect to a specific computer or service within a private local area network (LAN).

Gmail Video Chat is now available in Fedora

RPM version of Gmail video chat for Fedora is now available for download.
You can download the file from

Gmail video chat is now available for Linux Users

Gmail video chat now supports Linux, but it supports Debian/Ubuntu systems for now. RPM version for Red Hat/Fedora will be available soon.

You can download the plugin here.


How to install and configure VNC in Fedora 12

Open up your terminal and install tigervnc via yum.
Type this command in your terminal:

yum -y install tigervnc tigervnc-server

Edit the VNC configuration file

vi /etc/sysconfig/vncservers

and append these lines:

VNCSERVERARGS[1]="-geometry 800x600 -depth 16"

Where VNCSERVERS= is for configuring the username.

How to fix X11 Forwarding in CentOS 5

This tutorial describes how to fix the ssh X11 forwarding problem in CentOS 5.5 server.

Autoselected keyboard map en-us
ERROR: Failed to open display:

Make sure that the "xorg-x11-xauth" is also installed in your system. If not, this comm

yum -y install xorg-x11-xauth

Ensure that "X11Forwarding" is enabled in your ssh server configuration file. Edit the file "/etc/ssh/sshd_config".

How to disable IPV6 in Fedora 12 and CentOS 5.5

This is a quick tutorial on disabling IPV6 in Fedora 12 and CentOS 5.5

echo -e "install ipv6 /bin/true\nblacklist ipv6" > /etc/modprobe.d/blacklist-ipv6.conf

Stop ip6tables service and disable it from starting automatically at system boot.

service ip6tables stop
chkconfig ip6tables off

How to delete data inside MySQL table

If you want to delete a record from any MySQL table then you can use the delete command. The delete command is very similar to the update command.

delete from table where where_condition;

The delete statement deletes rows from a table.
The table is the table name.
The where clause specifies the conditions that identify which rows to delete.

How to update data inside MySQL table

Here's how to update existing data into MySQL database table.

update table set column='new_value' where where_condition;

The update statement updates columns of existing rows in the table with new values.
The table is the table name.
The set clause indicates which column to modify and the values they should be given.

How to insert data into MySQL table

Here is a general form of insert command:

insert into table (column1, column2) values (value1, value2);

The insert statement inserts new row into an existing table. The table is the name of the table into which we want to insert data, column1 and column2 are column names and value1, value2 are values for the respective columns.


How to convert xls files to csv in Linux

Install xls2csv

yum -y install xls2csv

To convert your xls file to csv, just type this command:

convertxls2csv -x filename.xls -c filename.csv

This script is very useful if you have a lot of excel files to convert. This will help you save a lot of time than converting it one by one.

for files in *.xls
convertxls2csv -x "$files" -c "${files%.*}.csv"
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