July « 2009 « Kurinchi Blogger Scribbles … :: Kurinchilamp: Blog on Linux Apache MySQL PHP and Softwares

Archive for July, 2009

Jul 31

2009

Ubuntu: Setting Root password

Last updated: July 28th, 2009

If Ubuntu server is installed anew, users tend to have a dilemma as to the steps involved in gaining access to the root account.

Root account exists but the password is not empty though.

The user should log in with the account he/she creates during the installation process.
(more…)

Tags: root login, root password, root password missing, set root password, ubuntu
Posted in LINUX, Tips, Tricks, Guides | No Comments »

Jul 30

2009

Ubuntu: Destination host unreachable

Last updated: July 28th, 2009

Possible causes:

Check how many network cards are installed in your system and if you are configuring the correct NIC card

Check the interfaces configuration settings

$ cat /etc/network/interfaces

Do not forget to restart the networking daemon after each change
$ sudo /etc/init.d/networking restart
(more…)

Tags: cannot connect to destination, network connection, network problem, network setting, NIC, ubuntu network
Posted in LINUX, Tips, Tricks, Guides | No Comments »

Jul 29

2009

Ubuntu: How to check if network configuration files work as expected?

Last updated: July 29th, 2009

After base Ubuntu installation, you have to configure the network interface file to get the network settings via DHCP/static IP address (if you haven’t configured during the initial installation). For this you need to edit /etc/network/interfaces file

$ vi /etc/network/interfaces
(more…)

Tags: pre installation steps, ubuntu server configuration steps
Posted in LINUX, Tips, Tricks, Guides | No Comments »

Jul 28

2009

Free Fugue Icons under CCA License

Last updated: July 27th, 2009

If you are a web designer or a programmer with a sense of site aesthetics, visit Pinvoke.com which has a HUGE! collection of icons (as of this writing 2225 icons) in PNG format distributed under Creative Commons Attribution License.

Yusuke Kamiyamane has given a thought in developing this extensive set of icons which will definitely be a handy collection in structuring the sites. Kudos to Yusuke.

Tags: cca, free icons, icons, png icons, royalty free icons
Posted in UI, CSS | No Comments »

Jul 27

2009

PHP Security: Preventing Session Fixation

Last updated: August 1st, 2009

Session Fixation is method by which an intruder creates a session id which gets carried on when a user comes with that path and continues his/her activity on a website.

For e.g. an intruder may create a link to a site called samplesite.com as <a href=”http://samplesite.com/cart.php?PHPSESSID=Ax23mDud” />Sample Site<a>

When a user clicks on this link the session id gets carried on to the site ‘samplesite.com‘. The intruder waits for the user starts to perform a transaction on the site and will take over vital details by intruding user’s activity on samplesite.com.
(more…)

Tags: php security measure, php session fixation, session, session fixation
Posted in Linux Server, PHP, Security | No Comments »

Jul 26

2009

Linux: How to change the default Run Level?

Last updated: July 22nd, 2009

To list the current run level
$ who -r
run-level 5 2008-07-22 21:35 last=5

To change the default Run level edit /etc/inittab

You can also switch to another run level number by issuing
$ init

For example,
$ init 3

Now the system switches from Run level 5 to Run level 3

To list the current run level
$ who -r
run-level 3 2008-07-22 22:35 last=5

In the above result notice the last part which states “last=5″. This indicates that the last run level was 5

When the system is running and if we want to apply patches or alter certain configurations, the above command comes in handy.

The other option to change the current level is
$ telinit <run level number>

Tags: Default Run Level, LINUX, Linux Run Level, Operating System
Posted in LINUX, Linux Server, Tips, Tricks, Guides | 1 Comment »

Jul 25

2009

Linux: How to find the current Run Level?

Last updated: July 25th, 2009

Default init level is set in /etc/inittab.

$ cat /etc/inittab (to display the init levels)

Inside that file, you can note a line which will state the run level number like
id:5:initdefault: (indicating run level 5 which means that the system is running with x windows)

To find the current run level you can execute the following commands

$ who -r
run-level 5 2008-07-22 21:35 last=5
which indicates that the system is in run-level 5

Other option to find the run level is
$ /sbin/runlevel
N 5

To find out what sub processes are associated with each run level you can go to
$ cd /etc/rcN.d/ (Where N denotes the run level number)

For example
$ cd /etc/rc1.d/
$ ls -l
This will list symbolic links to various processes associated with run level 1.

Tags: LINUX, Linux Run Level, Operating System, Run Level
Posted in LINUX, Linux Server, Tips, Tricks, Guides | 1 Comment »

Jul 24

2009

Ubuntu Release Download checksum

Last updated: July 24th, 2009

A quick note on the links related where to find the ubuntu releases and how to do a checksum to ensure that the downloaded copy

If you are downloading Ubuntu from the official site, MD5/SHA1 checksum (ubuntu hashes) for latest releases may not be listed there.

If it is not there, you can visit the site http://releases.ubuntu.com/. This site lists a comprehensive list of ubuntu releases and their checksums. Checksums ensure that the download is complete without corruption and is 100% accurate. So, it is always advisable to do a checksum after each download.
(more…)

Tags: bus architecture, checksum, md5, md5 checksum, ubuntu, ubuntu release download, ubuntu system information, uname
Posted in Linux Server, Tips, Tricks, Guides | No Comments »

Jul 23

2009

Linux: How many Run Levels are there and what are they?

Last updated: July 22nd, 2009

Linux systems have 7 Run Levels and they are as follows.

0 – system halt
1 – single user mode (system maintenance mode)
2 – multiuser mode without network access
3 – full multiuser mode with network access
4 – not used
5 – multiuser mode with X windows
6 – reboot or restart

Each run level in linux has a very specific purpose.

Run level 1 is also known as system maintenance mode and at this level the system prompt appears without root level password. It should be used only when it is absolutely necessary for system maintenance.

Run level 4 is not used and it can be used by the user to customize his own level.

Note: Solaris Run Level is different from Linux run levels.

Tags: 7 run levels, LINUX, Linux Run Level, Operating System, Run Level, Run Level states
Posted in LINUX, Linux Server, Tips, Tricks, Guides | No Comments »

Jul 22

2009

Linux: What is Run Level?

Last updated: July 22nd, 2009

Run Level is a term to indicate your computer’s state of operation. When your computer starts it initially starts the the first process called the init process. Init process in turn starts associated sub-processes for that state of operation.

Run Level is the state of the machine – indicating the processes and sub-processes that needs to be started in order for the Operating System to be in that state.

Tags: LINUX, Linux Run Level, Operating System, Run Level
Posted in LINUX, Linux Server | No Comments »

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Kurinchi Blogger Scribbles …

On Open Source Technologies

Archive for July, 2009

Ubuntu: Destination host unreachable

Ubuntu: How to check if network configuration files work as expected?

Free Fugue Icons under CCA License

PHP Security: Preventing Session Fixation

Linux: How to change the default Run Level?

Linux: How to find the current Run Level?

Ubuntu Release Download checksum

Linux: How many Run Levels are there and what are they?

Linux: What is Run Level?

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