Increase or decrease number of telnet session on Linux/Fedora

Edit the file /etc/xinetd.conf.
Change the parameter "instances" to a suitable value you need.
Save the file.
Restart xinetd service. [Command: service xinetd restart]

Optimizing MySQL Performance With MySQLTuner

MySQLTuner is a high-performance perl tuning script that will provide you with a report of a MySQL server’s health. Based on the statistics gathered, MySQLTuner will provide specific recommendations that will increase a MySQL server’s efficiency and performance. The script gives you automated MySQL tuning that is expected on the level of what you would receive from a MySQL DBA.

Installation:
Download perl script --->> wget http://mysqltuner.com/mysqltuner.pl
Change file permission --->> chmod +x mysqltuner.pl
Run --->> ./mysqltuner.pl


Install the Flash Plugin with Firefox on IBM XSeries X86_64

Follow the instruction from http://www.linuxheadquarters.com/howto/64-bit/flash64.shtml to download, install & enable flash plugin.

Intel® PRO/100 Network Adapter -- Device eth0 does not seem to be present, delaying initialization

Device eth0 does not seem to be present, delaying initialization ---

Some Intel Pro 100/1000 Network Adapter for PCI/PCIX slots comes without any EEPROM!!
This can be tested easily using dmesg command.
I faced such problem with a 100mpbs Intel® PRO/100 Network Adapter (PCI) with Fedora 6 (x86_64).

The command is dmesg | grep "e100" [for 100mbps cards]
The command is dmesg | grep "e1000" [for 1000mbps cards]

Result of the command in my case was:
e100: 0000:00:0d.0: e100_eeprom_load: EEPROM corrupted
e100: probe of 0000:00:0d.0 failed with error -11

The easiest way to overlook this failure is add some options to /etc/modprobe.conf file

alias eth0 e100
options e100 eeprom_bad_csum_allow=1

I added the green line above in the file /etc/modprobe.conf. Then simply restarted the system.
Yes now the problem is solved & the Network Adapter is now usable.

Prevent ping/icmp attack using kernel parameter

Prevent ping/icmp attacks using kernel parameter

Write the following line in the file "/etc/sysctl.conf"
net.ipv4.icmp_echo_ignore_all = 1
Save the file & restart network service [command: service network restart]
OR
Save the file & run "sysctl -p"

We can also change the value of this runtime kernel parameter to 0 (zero) using the command:
echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all

If the value is "1" -->> The system will ignore all icmp/ping requests.
If the value is "0" -->> The system will accept all icmp/ping requests.

Ext4 FS and File System Encryption in Fedora 9

New Ext4 File System support in Fedora 9

New features in Ext4 File System:

>> Delayed Allocation
>> Uninitialized groups
>> Online Defragmentation

More details at: http://fedoraproject.org/wiki/Features/Ext4

Encrypted File Systems

Now users don't have to bother to use a third party software to encrypt their files. This new feature will take care of data security.
Its a good and importance news for laptop users.

More details at: http://fedoraproject.org/wiki/Releases/FeatureEncryptedFilesystems

Installing Skype on Fedora 7

Installing Skype on Fedora 7
Instating Skype on Fedora is easy. The dependencies are only qt-4.4To install Skype using yum,

I have created a file called “skype.repo” in “/etc/yum.repos.d/” directory with the following content.

[skype] name=Skype Repository baseurl=http://download.skype.com/linux/repos/fedora/updates/i586/ gpgkey=http://www.skype.com/products/skype/linux/rpm-public-key.asc

Then, I have used the command “yum install skype” to download & install Skype and its dependencies (qt4 & qt4-x11).

Note: It may fail to install Skype with the error “GPG key parsing failed: No key found in given key data”.
If it is so, download the Skype rpm file from http://www.skype.com/download/skype/linux/choose/
Then install using “rpm –i skype-2.2.0xxxxxxxx.rpm”