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September 8, 2008

How do I disable the ping response?

Filed under: Fedora, linux, open source, Ubuntu, Uncategorized — Tags: — egoleo @ 3:37 pm

Usually a ping is used to check if a machine is up and to check the network status.

It is a small network packet sent to the machine. If the machine is up, an answer will be sent. The time needed to get the answer is called ping time or round-trip time.

The ping response from an IP indicates the machine is up.

Unfortunately this can be used to quickly scan an IP-range for reachable hosts.

This can be used to find potential hackable machines. If your machine doesn’t answer to pings, your chance to be seen is reduced. (That doesn’t mean your machine is more secure, the machine is just not that easy to be seen from the internet. Nothing more.)

Add the following line to your init script for the network (the name depends on the distribution you use):

echo 1 >/proc/sys/net/ipv4/icmp_echo_ignore_all

This disables ping responses.

To reenable, use the following command:

echo 0 >/proc/sys/net/ipv4/icmp_echo_ignore_all

To make this permanent set the following into /etc/sysctl.conf (if you have such a file)

net.ipv4.conf.icmp_echo_ignore_all = 1

July 31, 2008

Changing Server Timezone On Ubuntu

Filed under: linux, Ubuntu — Tags: , — egoleo @ 6:51 am

Is amazing how sometimes such small issues on linux can frustrate a linux user.

I’m currently reconfiguring a machine on the other side of the globe, so I want to get it to work to IST instead of EST.

A quick google brought up a rather complex way of doing it which sounded really complex to me, so I refined my query and found the same solution in the Ubuntu documentation.

Simply run the following command as root (or using “su”):
sudo dpkg-reconfigure tzdata

And just follow the instructions.

No silly reboots or other craziness required.

To keep your server’s time in sync with the rest of civilisation setup a cronjob to poll an ntp server once every 24 hours:
/usr/sbin/ntpdate yourfavouritentpserveraddress

Problem solved 🙂

June 2, 2008

Howto enable wireless on ACER 4520 on Ubuntu Hardy

Filed under: Acer, Ubuntu — Tags: , , , — egoleo @ 7:13 am

Just today i had all my configurations for my wifi card which is
Atheros Communications Inc. AR242x 802.11abg Wireless PCI Express Adapter (rev 01) wiped of after a Hardy upgrade. So below i fixed it. But i used it also for the first time when installing Hardy fresh.

1. Open you terminal

2. Get this version of madwifi:

wget -c http://snapshots.madwifi.org/special/madwifi-hal-0.10.5.6-r3698-20080604.tar.gz

3. Untar the downloaded package:

tar xvf madwifi-ng-r2756+ar5007.tar.gz

4. Get inside the unpacked directory:

cd madwifi-ng-r2756+ar5007

5. If you haven’t compiled anything from source before on your linux then you propably need the build essential package:

sudo apt-get update && sudo aptitude install build-essential

6. Now you can build your madwifi and install the modules:
make

sudo make install
sudo modprobe ath_pci
sudo modprobe wlan_scan_sta

The last 2 commands can cause some complications on some systems. If they do check your System >> Administration >> Restricted Drivers Manager and disable atheros here. Then try again.

7. Now restart your computer and you should be able to see any aviable networks in your Network Manager.

May 27, 2008

Installing Ubuntu7.10 on Acer4520

Filed under: Acer, Ubuntu — egoleo @ 7:35 am

System Specs
………….
Acer Aspire 4520
AMD64 Athlon X2
Nvidia GeForce 7000M
160 Gig
802.11b/g WLAN
1Gig DDR2

I have been trying for the past weeks since i had this laptop with
the above specs to run ubuntu7.10 but all failed. So i finally got myself
into runing 7.04 rather. But have finally gotten a way to run 7.10 on it and
this is how i did it.

I realised that anytime i installed the 7.10 and i reboot, it hangs at the splashcreen and so for some reason i felt it might be the menu.lst file so edited couple of times but nothing happened. so WHat i finally did was to get the 7.04 ubuntu cds and install and upgrade that to 7.10. And that worked. But when i upgraded the kernel to the original one used by 7.10, i got the same splashscreen hanging again. So i kept the upgrade on but now uses the 7.04 kernel rather instead of the 7.10 kernel which still works fine for me.

But after that, it wasnt all dont since it could not detect some of my hardware devices like the wireless and vga card.

1. to fix the X.
………………

I used the ubuntu livecd and mounted the installed my root(/) partition to get aaccess to xorg.conf file. commands below.

> mkdir /media/system
> mount /dev/sda1 /media/system

The above could be different for you. i mean the mount points

> cd /media/system
> vim etc/X11/xorg.conf

Once you are in this file, look for this lines

Section “Device”
Identifier “nVidia Corporation NVIDIA Default Card”
Driver “nvidia”
BusID “PCI:0:18:0”
EndSection

change the “Driver nvidia” part to “Driver vesa” instead and save and
reboot without the livecd.

2. how to fix sound too
………………………
simple first download the packages from the below site and copy them into one folder

http://www.alsa-project.org/main/index.php/Download

next

you need one of the c libraries and curses libraries for this i guess you are done with adding extra repositories if not message me i will explain

open the terminal and fire the following
sudo synaptic

and next search for g++ library

after that search for curses library for c

after this automatically done by the synaptic

go the folder where you have downloaded the packages and extract each and everything like below

> tar xjf alsa-(name of the package)

after extarcting just type this

> cd alsa-(extracted package)

next

> ./configure

next

> make

next

> sudo make install

do the above for all packages u just downloaded from the above link.
and afterward just reboot ur machine. u should hear sound now 🙂

3. howto fix wireless
………………….

Before we start, we have to make sure that MadWifi drivers don’t get loaded at boot, since we could have a conflict between the two. You can do this typing this:

blacklist ath_pci

in /etc/modprobe.d/blacklist file or by using the restricted driver manager:

> vim /etc/modprobe.d/blacklist

Install ndiswrapper
> sudo apt-get install ndiswrapper
> sudo apt-get install ndisgtk

you can also install ndisgtk or use synaptic instead of the console

after, download the Atheros driver
form this link http://www.atheros.cz/download.php?atheros=AR5006EG&system=1
anyway that is the link i used in getting mine to work.

afterwards you need to unzip the file just downloaded from the link

Install the .inf file in ndiswrapper, using ndisgtk or the command
> sudo ndiswrapper -i net5416.inf
from the unzipped file

Save ndiswrapper module configuration files by issuing the command:
> sudo ndiswrapper -ma && sudo ndiswrapper -mi

You can now reboot and bravo. u can check to see u should be done now.

May 19, 2008

How to install perl modules through CPAN on ubuntu hardy server

Filed under: Perl, Ubuntu — Tags: , — egoleo @ 1:53 pm

This assumes that you have grabbed a copy of the ubuntu hardy server
cd from the ubuntu.com website.

1. Install all dependent packages for CPAN
sudo  apt-get install build-essential

2. invoke the cpan command as a normal user

$cpan

But once you hit on enter for “cpan” to execute, you
be asked of some few questions. To make it simple for
yourself, answer “no” for the first question so that
the latter ones will be done for you automatically.

3. Once the above is done, you will be present with the cpan
prompt. now enter the commands below

make install

install Bundle::CPAN

4. Now all is set and you can install any perl module you want. examples of what installed below

cpan prompt>  install  IO::File
cpan prompt>  install  Net::SMTP_auth
cpan prompt>  Email::MIME::Attachment::Stripper
cpan prompt>  Mail::POP3Client

October 26, 2006

how to install chm on linux

Filed under: Ubuntu — egoleo @ 10:51 pm

I had some tutorials from a friend. But all the files were having a .chm extension. so i couldn’t view them with my linux system. i decided to google and i realised that it was a micrsoft format. But i also found out that i can have a similar program to view thm on linux. The package name is XCHM.

how to install chm == xchm on ubuntu anddebian.

sudo apt-get install xchm.

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