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Tweaking dhcp client configuration to change the default DNS servers to Open DNS

The DNS servers of my ISP is always behaving erratically. The DNS look up times are abysmally large and some times I get an address not found error while browsing. On ubuntu/debian systems the DNS servers are specified in /etc/resolv.conf. I tried to edit /etc/resolv.conf and put open dns servers as default DNS servers. But, my ISP supplies their DNS server address along with IP address for the system via DHCP. Every time my system renews its DHCP lease. my /etc/resolv.conf is also rewritten with their DNS address.

My /etc/resolv.conf ( supplied by ISP) looks like this.

$ cat /etc/resolv.conf
domain asianetindia.com
search asianetindia.com
nameserver 202.88.238.3
nameserver 202.88.238.5
nameserver 202.88.231.2

There is a trick I used to make Open DNS servers as my default DNS server.

Edit /etc/dhcp3/dhclient.conf and look for the line.
#prepend domain-name-servers 127.0.0.1;
Add the following line immediately below the above line.

prepend domain-name-servers 208.67.222.222;
prepend domain-name-servers 208.67.220.220;

You can also put any other DNS servers.

Now renew the lease with

$ sudo dhclient eth0

The new /etc/resolve.conf looks like this.
$ cat /etc/resolv.conf
domain asianetindia.com
search asianetindia.com
nameserver 208.67.220.220
nameserver 208.67.222.222
nameserver 202.88.238.3
nameserver 202.88.238.5
nameserver 202.88.231.2

DNS look up is made from open dns.

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Ubuntu Linux root password default password zz

Q. I have just installed Ubuntu Linux. But, what is the default root password? I can only login as a normal user.

A. This is the mystery for most users - you didnt set a root password, so what is it?
The root user can do anything as this a/c has full access to system. So using root account for daily work can be dangerous.

To be frank root a/c is locked by default under Ubuntu Linux. Therefore, you cannot login as root or use su - command to become superuser.

To run all administrative command use sudo command. sudo allows a permitted user to execute a command as the superuser or another user. Ubuntu setup your default account (the one created during installation) to run all administrative commands.

For example create a new user called bar, you need to type sudo command as follows:
$ sudo adduser barPassword:
When sudo asks for a password, it needs YOUR OWN Password; this means that a root password is not needed.

Here are few more examples.
Task: Start / stop / restart services stored in /etc/init.d/ directory
$ sudo /etc/init.d/ssh stop$ sudo /etc/init.d/networking restart
Task: Avoid typing sudo each and every time

Note that this is not recommended until and unless you are an expert and aware of what you are typing:
$ sudo -i

Above command will start /bin/bash as a root shell so that you can enter a root user command w/o using sudo.

http://www.cyberciti.biz/faq/ubuntu-linux-root-password-default-password/

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Ubuntu Change Default Editor

Your terminal should have a default editor. This is what is used whenever you run commands like

. It may not be set to what you like, or your preferences may have changed. To change it, simply run the following command:

sudo update-alternatives --config editor
# You may also need to run this one for crontab
select-editor

Now enter the number representing the editor you would like to default to

Now that is set, you can use the editor command in substitute for

or . This is great for people who write tutorials because now we dont have to assume what you like to use. For example, I will try to make sure my tutorial steps are like below:

editor my-config-file.txt

Instead of:

vim my-config-file.txt

References

• How-To Geek - Change the Default Editor From Nano on Ubuntu Linux

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Ubuntu Setting Deluge as the default bittorrent client

I got a tip that Deluge will work way more reliably than the default client of Ubuntu, Transmission. Installing is easy enough, just type:

 sudo apt-get install deluge 

In the settings I also set it to handle magnet files, but it didnt work out-of-the-box. I had to issue the following command too, to make it work as intended:

 gvfs-mime --set x-scheme-handler/magnet deluge.desktop 

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