Grub error 15

Generally it occurs when /boot and / are mounted on differant partations
FIx : install grub on /boot partation of your hard drive

installing wifi driver on fedora 16

Getting gome3 and Fedora 16 was great but until i realized that it does not support wifi ( by default ) as againt Ubuntu .
so here's a smartest and quickest method to get wifi rolling on fedora 16

As a root(super) user enter the following four commands and then reboot to get WIFI Up and running

#rpm -ivh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm

#rpm -ivh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

#sudo yum update

#yum install kmod-wl

Using Gmail to fight SPAM

The Problem


Spam is nothing but unsolicited mails being send to your inbox daily claiming to clear your depts or promising more hair on your scalp or blah blah blah..........


The Remedy

Although a lot of tools are available in the market for finghting this modern age plague of the mailing system like SpamAssassin and MailWasher but my personal favourite is Gmail and following are the reason's for it.


1. Gmail has a powerful spam filter that does a great job filtering out junk( for me it works to the extent of 99..99%)

2 It's FREE


The Trick

Google's free web based Gmail is both an e-mail client and e-mail host .Use gmail e-mail client feature to fetch mail from your another e-mail account so it will have to pass through Gmail's spam filter and hence your life will be much better with less spam.


Lock n Load

Here's a quick insight into the process.

Say i have an e-mail account as bogus@mydomain.com that get's bombard with spam now i will configure my gmail as a pop client for this account fetching mail from it and appling it's powerful spam filter on it hence getting rid of spam to a great extent.


1 . Create a Gmail account ( no problem if you already have one.....lolz)

2 Click on Gmail's settings and open Accounts Tab

3 Select Add another Gmail Account and after verification of your mail account (bogus@mydomain.com in my case) Gmail will start fetching messges from the account ) At this point Gmail Automatically Scan's for spam when it retrieves mail from the alternate account.

4 Now if you do not want the browser-based Gmail as your primary address co configure outlook or thunderbird to receive mail's from your Gmail account.



Now the only change you will notice is that now your mail is less spammy besides this there will be no other visible involvement of google.
Also if accidently some of your important mail have been marked as Spam then they can always be reterieved from the Spam folder.

DNS Round Robin

Round robin DNS is a method of maintaining high-availability and fault tolerance with the help DNS server . RrD can also be thought as poor man's clustering in a very loose sense , though useful it has it's disadvantages also .For more on the topic refer to this wikipedia's page.

SCENARIO

Now please allow me to do some ASCII art

_
10.0.0.1 (web.example.com) | example.com
10.0.0.2 (web.example.com) |-------> DNS <<----->> Client
10.0.0.3 (web.example.com) |

(Wow what a magnificent piece of art )
As is depicted in the above diagram the DNS server has authority for example.com


I implemented Round robin DNS using bind9 and Ubuntu Server 8.10 but it can easily be implemented on any other Linux systems


IMPLEMENTATION

BEFORE

Before multiple duplicate servers for www.example.com we had just a single server for www.example.com and the zone file for example.com looked something like this.

Snippet from the zone file of example.com

www.example.com. IN A 10.0.0.1


AFTER


Now to share the load on the web server of example.com across three servers simply define the define multiple A records with the same name and different IPs in the zone file as in the example below.


www.example.com. IN A 10.0.0.1
www.example.com. IN A 10.0.0.2
www.example.com. IN A 10.0.0.3

The DNS will deliver all the IP addresses defined, the first IP address in the list will be in a default round robin (controlled by the rrset 'named.conf' directive). The WEB servers must all be exact replicas of each other in this scenario.

You can control the order of RR that BIND supplies in response to queries by use of a rrset-order option which works for any set of equal records. The default behaviour is defined to be random-cyclic - a random selection of the initial order thereafter cyclic (round-robin)

Install Fedora10 to a flash drive using windows

Prerequisites for Creating a Live USB Fedora:

• Windows host PC (Tested on Windows XP)

• 1GB+ USB flash drive

• liveusb-creator-3.2.zip

• Fedora10 Live iso image

Steps for creating a live Fedora USB

1) Format your pen drive with FAT file system

2) Download liveusb-creater

3) Extract liveusb-creator-3.2.zip to your PC

4) Navigate to the liveusb-creator-3.2 folder and click liveusb-creator.exe to launch the tool

Although the process of creating a fedora10 usb stick is straingforward from there yet a quick insight into the process goes as follows

a) Use existing live cd ( Browse to the Fedora10 live iso path) or alternatively Download Fedora10
b) Choose the persistant overlay size as per your requirement
c) Select target device to point to your pen-drive
d) Click Create Live USB to begin the creation process




After the completion of the above process restart your PC with your pen drive plugged in ( don't forget to modify your BIOS settings i:e making USB as the first boot device) .If all goes well you will be able to boot your Fedora10 from the pen drive.

Linux Wake on LAN

WakeOnLan allows you to switch your PC without physically accessing it by sending a magic packet to it.For more information visit this Wikipedia's page

Check weather WOL is supported by your NIC

Downlad and install ethtool and then issue the command sudo ethtool eth0 { or what ever your ethernet device is and you will get something like this

linux@ubuntu:~$ sudo ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pg
Wake-on: d
Current message level: 0x000000ff (255)
Link detected: yes

check out the line Supports Wake-on ( as highlighted above) if it contains a g flag the your NIC supports WOL


Enabling WOL

To enable WOL issue the command sudo ethtool -s eth0 wol g this can be verified by checking the Wake-on flag

linux@ubuntu:~$ sudo ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pg
Wake-on: g
Current message level: 0x000000ff (255)
Link detected: yes



Note down the mac address of the machine

To get the mac address use the command sudo ifconfig eth0

linux@ubuntu:~$ sudo ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:1d:72:04:59:25 inet addr:192.168.155.6 Bcast:192.168.159.255 Mask:255.255.248.0 inet6 addr: fe80::21d:72ff:fe04:5925/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:14840 errors:0 dropped:0 overruns:0 frame:0 TX packets:2521 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2362485 (2.3 MB) TX bytes:608765 (608.7 KB) Interrupt:16


Install wakeonlan package on a different machine

Install the wakeonlan package in the machine from where you need to send the magic packet to switch on your server.

Finally, Switch ON the machine remotely without physical access
When the server is not up, execute the following command from another machine which is connected to the same LAN. Once the magic packet is sent, the remote system will start to boot.


Enabling WOL across multiple reboots

The WOL feature has to be enabled manually after every reboot in order to avoid this problem just install the following script in /etc/rc.d directory by using chkconfig (Red hat or fedora) or update-rc.d (ubuntu or debian)

#!/bin/bash
DEV="eth0"
FEATURE="wol"
FLAG="g"
ETTOOL="ethtool"
$ETTOOL -s $DEV $FEATURE $FLAG
n=$?
if [ $n -eq 0 ]
then
echo "WOL enabled successfully "
else
echo "Cannot enable WOL"
fi

Say hello to TUX

How many a times it has happened that many a people try Linux for some time and then dump it ? well if u ask me I'll say plenty of times.It all starts like this.
You are bored of using a proprietary OS over the ages and want to try something new also now a days tere is a lot of buzz about Linux , so it all boils down to you calling your (Geek) friend and asking him to install Linux on your PC ( although there is no need of any external f1(help) , any one can install Linux[Ubuntu] easily).
After the installation is finished you are all set to breathe free in the Open Source World so you try your Linux for some time and then you start feeling "Oh God my proprietary OS was better as it played all my videos ....or where is my i tunes...." and things like that and finally you handcuff yourself to the proprietary OS and probably never think of coming out of it.
Let me tell you there are open source alternates to almost any proprietary software on this planet , some of the popular open source software alternatives to proprietary softwares can be found on the sites

http://whdb.com/2008/the-top-50-proprietary-programs-that-drive-you-crazy-and-their-open-source-alternatives/


But how to get these working on your Linux(Ubuntu 8.10) box ? The following tutorials links prove handy in getting your favorite open source software up and running on your box

https://help.ubuntu.com/community/InstallingSoftware
http://linuxgator.org/forums/viewtopic.php?f=15&t=1067
http://www.ehow.com/how_2243216_install-software-linux-using-synaptic.html
http://simplyubuntu.wordpress.com/2006/06/27/a-beginners-guide-to-installing-programs-in-ubuntu/