Thursday, September 23, 2010

Installing Ubuntu Linux On windows 7 or Vista Dual boot

My Brother's HP laptop contains only Vista now he want to install Ubuntu on it.
Possible solutions 1) format the entire hard disk install ubuntu linux.
2) use the Dual boot option. [ will discuss here ]

To get the Dual boot option with windows we need to install windows first as far as I know.
We need to delete a logical drive from windows to install linux. But The laptop is containing only one drive.So we need to make the partition with out corrupting the existing geniuen windows.

Go to administrative tool in that we can see Disk management there we can see windows hard disk drive C (guess) Right click on that click on shrink volume..So to create new drive give some 30 gb ( I gave 50 gb).
By using shrink option operating system won't get corrupted and by which we can create a drive..Thanks to shrink partition.

Now delete the newly created drive from windows, that's it.
This newly created and deleted partition is used to install ubuntu..


Follow the above link to install ubuntu
Select the option "Use the largest contigous space" ( it will take the disk space which we have deleted above by shirnking/some how ) .

Done.

Linux installation on windows ..Here Shrinking is the Helping point..With out knowing shrink I have formatted a windows some time back :(.. recently I came to know So to help others I mam doing this post. ..Comment here if it helps you :)

Forgot to tell you while installing on my Brother HP laptop ,it was containing HP recovery back up which is of around 10gb in size .which was not allowing us to install linux so we have taken that backup into my laptop and deleted that recovery files..Then only we were able to install .I don't know what we did was wrong or right But we were happy by doing that.. :)

Wednesday, September 1, 2010

To Check Port is open or not

Before trying to connect a remote server it is better to check that sever is listening at the expected port ( Example mysql listens at 3306 and ssh 20 )

>telnet ip port

For example ip address 123.34.23.37 and I want to do ssh which listen by default 22
So need to check whether port 22 is listening then command would be :
>telnet 123.34.23.37 22
Above command will return some junk characters then it means open.
Otherwise it will return "telnet: Unable to connect to remote host: Connection refused"
that means its not opened..
Possible reasons : firewall is blocking or no service at that port to listen.

Remote Access to Mysql ubuntu

This link was good

http://ubuntu-commands.blogspot.com/2008/11/how-do-i-enable-remote-access-to-mysql.html

Copy & Pasted & EDITED the content from above link here ( for my reference)

By default, MySQL database server remote access disabled for security reasons. However, some time you need to provide the remote access to database server from home or from web server.
MySQL Remote Access

You need type the following commands which will allow remote connections:
Step # 1: Login over ssh if server is outside your IDC

First, login over ssh to remote MySQL database server
Step # 2: Enable networking

Once connected you need edit the mysql configuration file my.cfg using text editor such as vi.

* If you are using Debian Linux file is located at /etc/mysql/my.cnf location
* If you are using Red Hat Linux/Fedora/Centos Linux file is located at /etc/my.cnf location
* If you are using FreeBSD you need to create a file /var/db/mysql/my.cnf

# vi /etc/my.cnf
Step # 3: Once file opened, locate line that read as follows

[mysqld]

Make sure line skip-networking is commented (or remove line) and add following line

bind-address=YOUR-SERVER-IP

For example, if your MySQL server IP is 65.55.55.2 then entire block should be look like as follows:
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/English
bind-address = 65.55.55.2
# skip-networking
....
..
....Where,

* bind-address : IP address to bind to.
* skip-networking : Don’t listen for TCP/IP connections at all. All interaction with mysqld must be made via Unix sockets. This option is highly recommended for systems where only local requests are allowed. Since you need to allow remote connection this line should removed from file or put it in comment state.

Step# 4 Save and Close the file

Restart your mysql service to take change in effect:# /etc/init.d/mysql restart
Step # 5 Grant access to remote IP address

# mysql -u root -p mysqlGrant access to new database
If you want to add new database called foo for user bar and remote IP 202.54.10.20 then you need to type following commands at mysql> prompt:mysql> CREATE DATABASE foo;
mysql> GRANT ALL ON foo.* TO bar@'202.54.10.20' IDENTIFIED BY 'PASSWORD';
How Do I Grant access to existing database?

Let us assume that you are always making connection from remote IP called 202.54.10.20 for database called webdb for user webadmin, To grant access to this IP address type the following command At mysql> prompt for existing database:mysql> update db set Host='202.54.10.20' where Db='webdb';
mysql> update user set Host='202.54.10.20' where user='webadmin';
Step # 5: Logout of MySQL

Type exit command to logout mysql:mysql> exit
Step # 6: Open port 3306

You need to open port 3306 using iptables or BSD pf firewall.
A sample iptables rule to open Linux iptables firewall

/sbin/iptables -A INPUT -i eth0 -p tcp --destination-port 3306 -j ACCEPT

OR only allow remote connection from your web server located at 10.5.1.3:

/sbin/iptables -A INPUT -i eth0 -s 10.5.1.3 -p tcp --destination-port 3306 -j ACCEPT

OR only allow remote connection from your lan subnet 192.168.1.0/24:

/sbin/iptables -A INPUT -i eth0 -s 192.168.1.0/24 -p tcp --destination-port 3306 -j ACCEPT

A sample FreeBSD / OpenBSD pf rule ( /etc/pf.conf)

pass in on $ext_if proto tcp from any to any port 3306

OR allow only access from your web server located at 10.5.1.3:

pass in on $ext_if proto tcp from 10.5.1.3 to any port 3306 flags S/SA synproxy state

Step # 7: Test it

From remote system or your desktop type the command:
$ mysql -u webadmin –h 65.55.55.2 –p
Where,

* -u webadmin: webadmin is MySQL username
* -h IP or hostname: 65.55.55.2 is MySQL server IP address or hostname (FQDN)
* -p : Prompt for password

You can also use telnet to connect to port 3306 for testing purpose:$ telnet 65.55.55.2 3306

Create a user at % ( only this user can remotely connect)
mysql>CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%'
-> WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;
to create user http://dev.mysql.com/doc/refman/5.1/en/adding-users.html