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firewall is a device that filters traffic between networks, at least two. To purchase a firewall you can buy an appliance or physical device. It can also be implemented using an ordinary computer with two network cards. In this post we present a simple script to have a Firewall installed on Linux server, also explains some theory about the workings of iptables.

Beginning, there are two types of firewall:

Host or installed on the computer itself, which protects the personal computer.

network firewall, which protect a set of computers, monitors and write protocols and reports and logs are more expensive.

Before implementing a firewall is necessary to develop a security policy for the benefit of users, in other words you need to think:

service

Reason People affected with the service

List and other services establish criteria to help secure the services Writing a report that considered rape if another type of access.

A firewall has two basic functions: ACCEPT (ACCEPT) and rejected (REJECT).

IPTables is in the kernel Linux from kernel 2.4. onwards. Iptables was created to apply filter rules. The rules are declared and submitted to the kernel, then, when the kernel receives the packet from the network, see the rules and decide an action effect that can be:

Filter: Management of the network. Its rules are: INPUT, OUTPUT and FORWARD

Nat: Altering packets that create new connection. Its rules are: PREROUTING and POSTROUTING

Mangle: Modify the package. Its rules are: PREROUTING and POSTROUTING

In the diagram we see that INPUT FORWARD and OUTPUT are the three types of filtering of iptables. But before being processed may be preceded by NAT which can lead to another IP packet. For packages going to the same team applies INPUT and OUTPUT. For packages that are applicable outside FORWARD.

Another list of keywords in iptables are:

ACCEPT: Package is accepted and can travel to the destination

DROP: The packet does not have access to the system and not sent back to the server.

QUEUE: The package passed to user space. REJECT: Unlike DROP, the packet is sent and sends an error to the sender of the package.

For example, to open ports navigation type in linux console:
iptables-A INPUT-p tcp - sport 80-j ACCEPT
• iptables-A INPUT-p tcp - dport 80-j ACCEPT

mail server on port 25:

iptables-A INPUT-p tcp - dport 25-j ACCEPT iptables-A INPUT
• -p tcp - sport 25-j ACCEPT
To make a simple iptables firewall, the first thing is to configure the linux server with two and configure network cards over the Internet between the cards. For the first card will go the internet and the second, the internal network.
is important to note that the firewall is a mechanism that refers to rules that declare, therefore there will be consideration to write and understand each parameter if we are to have a good skill in configuación firewall. The configuration of a firewall is not an easy task, as it increases the amount of resources that will use the network traffic that controls the firewall, as a new laptop, video conferencing, more complex configurations requires rules protect the network.

Script to make a simple firewall:

# remove the Firewall iptables-F iptables-X iptables-Z

# default policy all closed
• INPUT DROP iptables-P iptables-P OUTPUT
• DROP iptables-P FORWARD DROP #

Opening ports iptables-A INPUT-p tcp - sport 80-j ACCEPT iptables-A OUTPUT
-p tcp - dport 80-j ACCEPT iptables

-A INPUT-p udp - sport 53-j ACCEPT iptables-A OUTPUT -p udp - dport 53-j ACCEPT iptables-A INPUT-p tcp - sport 443-j ACCEPT iptables-A OUTPUT

-p tcp - dport 443-j ACCEPT # Converting

Firewall Forward mode echo 1
> /
proc/sys/net/ipv4/ip_forward iptables-t nat-A POSTROUTING-s

10.0.0.0 / 8
• -o eth0-j MASQUERADE #
Opening ports for FORWARD iptables-A FORWARD-p tcp - sport 80-j ACCEPT
• iptables-A FORWARD-p tcp - dport 80-j ACCEPT iptables-A
• FORWARD-p udp - sport 53-j ACCEPT iptables-A FORWARD
-P udp - dport 53-j ACCEPT iptables-A

FORWARD-p tcp - sport 443-j ACCEPT iptables-A FORWARD
-p tcp - dport 443-j ACCEPT





#

EOF





To extend the knowledge about iptables can visit the Tutorial by Oskar Andreasson: http://www.frozentux.net/iptables-tutorial/iptables-tutorial.html

The project netfilter / iptables:

http://www.netfilter.org/projects/iptables/index.html

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This post has
item Steps to create cubes in SQL Server OLTP - Business Intelligence



To run the project can download the OLTP database bucket list:
http://www.4shared.com/file/BdWZ09_w/Northwind_OLAP.html
. Unzip in a single location *. bak file, make sure you have installed on the server and client computer Analysis Services and SQL Server Business Intelligence Development Studio. If correct follow the instructions:


Step 1: Connect to Motor

database and restore the database NorthWind_OLAP. Look at the diagram of relationships. In the example, the database has 5 dimensions and Sales_Fact is the central table.











Step 2: Open
SQL Server Business Intelligence Development Studio.
Use the option to create a new database. In "Name the database" Type Northwind_Mart and set the impersonation mode. For example use "Use the credentials of current user"



Done. The basis for the consultations were carried out successfully.

Step 3:
In Visual Studio create a new solution for Bussiness Intelligence and connect to the database Northwind_Mart. Follow the wizard's instructions.

Step 4:
As a result of previous step we obtain a diagram of the database. It is necessary to define the dimensions. In Solution Explorer to find the node dimensions and create a new dimension by using the context menu in the node.



Select the elements or fields that are present in dimensions.

Select the table that will be the center of the combinations or have the measurements. For example select Sales_Fact.




Continue adding dimensions to complete the entire database schema.


Step 5:

After the configuration of dimensions is necessary to process the cube. In the Hub node in Solution Explorer context menu used to start the check.

"Processing Hub" to verify if the configuration database Northwind_OLAP is suitable for cube queries. If an error occurs, reconfigure the hub using the error descriptions listed in the log.

Step 6 Step 6 If successfully completed, there is only connected to the hub for the outcome of the consultation.
In the Browser tab drag the dimensions to the area of \u200b\u200bconsultation and see the result.

The quality of information received depends on the management of the correct size and design of the cube. Good job!