Computer Port

Most of the people assumes that port are present physical which needs to connected physically . Well ports are logical number assigned in a hardware , which is assigned a specific task. Ip Addresses are branched into ports, so that one ip address can be used by multiple programs to send and receive data at the same time. Ports make it possible for you to check your email and browse the web at the same time. This is possible because browsing the web uses port 80, and getting your email uses port number 110.

You can think of a port as a path for data. When a program is using a port to send or receive data, think of the port as blocked. Meaning that no other program can use a port when it is already in use by a program.In both TCP (Transmission Control Protocol) and UDP, each packet header will specify a source port and a destination port, each of which is a 16-bit unsigned integer (i. e. ranging from 0 to 65535), as well as specifying the source and destination network addresses (IP-numbers) among other things.

A process may "bind" to a particular port to send and receive data, meaning that it will listen for incoming packets whose destination port matches that port number, and/or send outgoing packets whose source port is set to that port number. Processes may also bind to multiple ports.

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What is SSL ?

Secure Sockets Layer (SSL), are cryptographic protocols that provides secure communications on the Internet for web browsing, e-mail, Internet faxing, instant messaging(IM) and other data transfers.Specially those who run important part of their business on internet must be aware that the Internet is your gateway to millions of potential new customers. Moving your business online provides the convenience and accessibility your customers and partners demand, helping you to stand out from the competition.

As organizations provide more services and transactions online, security becomes a necessity. Customers need to be confident that sensitive information such as a credit / debit card number is going to a legitimate online business. Organizations need to keep customer information private and secure.

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Script Injection

As technology progresses hackers look for techniques to hack your servers . Most common technique is Script injection attack, which occur when a hacker takes a few lines of malicious programming code and enters it in to a form on your Website and then submits the form. If your Website is data driven then chances and you have forms on your Website. Hackers will often inject scripts in to your forms and try to do the following :

Mislead the system in to thinking they are a authorized or legitimate registered user
Try and modify your data on the data server
Try and generate reports from your database without your consent
Try and generate reports about your file structure or security

There are a million things a hacker can do if he can get access through script injection attacks. Most Web servers now combat this method of hacking automatically. Anything that looks like a script is rejected by the server and by default. Microsoft is dealing with it on the .NET framework.

So the most important thing to prevent script injection attacks:

1.Programming languages contain many characters and certain otherl keywords that are not conventional to the English language. For example, no one has a name that has the characters "*", or "%", or "@", or "!" or "<" or ">" in it. All of which are common place in all programming languages. These types of characters should be rejected by your forms whenever possible. This is the most simple way to tackle this problem.

2.Validate the data before submitting Eg: If you are asking the user for a name then make sure it does not contain numbers.

3.Limit the amount of characters a user can type in to each form.

4.Input encoding

5.Output encoding

Other type of injection is SQL injection , which will be discussed in the coming post

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SQL SERVER : INDEX

How do we Create INDEX in SQL SERVER ?

Indices are created in an existing table to locate rows more efficiently and quickly. It is possible to create an index on one or more columns of a table, and each index is given a name. The users cannot see the indexes, they are just used to speed up queries.

Why do we Create INDEX in SQL SERVER ?

Updating a table containing indexes takes more time than updating a table without, this is because the indexes also need an update. So, it is a good idea to create indexes only on columns that are often used for a search. Index are going to boost the performance when applied on large databases but you may not see much performance difference when applied on small databases.

What are various types of INDICES in SQL SERVER ?

1. Unique Index
2. Simple Index

How do we create UNIQUE INDEX ?

SYNTAX:
CREATE UNIQUE INDEX index_name
ON table_name (column_name)

A unique index means that two rows cannot have the same index value.


How do we create SIMPLE INDEX ?

SYNTAX:
CREATE INDEX index_name
ON table_name (column_name)

When the UNIQUE keyword is omitted, duplicate values are allowed.

What is IIS ?

The acronym IIS stands for Internet Information Services which can turn a computer into a Web server that can provide folowing services

• World Wide Web publishing
• File Transfer Protocol (also known as FTP)
• Network News Transfer Protocol (also known as NNTP)
• Simple Mail Transport Protocol (also known as SMTP)

You can use IIS to host and manage Web sites and other Internet content once you obtain an IP address, then register your domain on a DNS server, and configure your network .

The various versions of IIS are as follows as on 01/01/2008

• IIS 1.0, Windows NT 3.51 available as a free add-on
• IIS 2.0, Windows NT 4.0
• IIS 3.0, Windows NT 4.0 Service Pack 3
• IIS 4.0, Windows NT 4.0 Option Pack
• IIS 5.0, Windows 2000
• IIS 5.1, Windows XP Professional
• IIS 6.0, Windows Server 2003 and Windows XP Professional x64 Edition
• IIS 7.0, Windows Vista and Windows Server 2008

IIS 5.0 and higher versions support the following authentication mechanisms:

1. Basic access authentication
2. Digest access authentication
3. Integrated Windows Authentication
4. .NET Passport Authentication

RSS

RSS was developed by Dave Winer in the year 1997.It is an acronym for Really Simple Syndication which allows you to syndicate your site content. It provides an easy way to share and view of headlines and content .Moreover what u want to view, it can be personalized.RSS is a method that uses XML to distribute web content to other web sites.

Without RSS, users will have to check your favourite site daily for updates. This may be too time-consuming for many users. Many sites use RSS and many people are understanding its usefulness with each passing day.With the help RSS, information on the internet is becoming easily visible and web developers can spread their information more easily and swiftly to special interest groups.

Symbian Operating System

Symbian is an advanced operating system basically meant for mobile phones and other small hand held devices. It is designed for specific requirements of the latest 2.5G and 3G mobile phones. Symbian OS combines the power of an integrated applications environment with mobile telephony, bringing advanced data services to the mass market.

Latest version of Symbian OS as on 01/01/2008 is version 9.5, this latest evolution of Symbian OS, delivers over 70 new features for high-performance, more powerful smartphones at mass market costs. Many NOKIA and other leading mobile phone brands have symbian operating system in them.

In simpler terms , what windows does for your computer ; symbian does for your mobile phones.

Google's GTALK

Google Talk is Google's instant communications service. It very simple hence faster with almost no bugs. More over if you want to do voice chat , it gives better quality with almost no breaks when compared to yahoo messenger or msn messenger .
Important facts of Google Talk Client:

* Quick Download
* Make free PC-to-PC voice calls
* Send and receive voicemail
* Transfer unlimited files and folders
* Receive chat and email notifications
* Archive your chats in Gmail
* Cost: Free

Click here to Visit GTalk Website

It will take a few seconds over a broadband connection or about three minutes over a typical modem. Google Talk requires Windows Vista/XP/2000 with a minimum 56k connection speed