Search Engine Optimization

What is Search Engine Optimization?

SEO stands for Search Engine Optimization. SEO is the process of affecting the traffic from the "free", "organic", "natural", "editoral" or "earned" result on search engines. By using Search Engine Optimization one can improve the visibility of a website over internet. It is a technique which supports search engines to find and rank your website heigher among millions of websites. So, this technique is fruitful for you to get more traffic over the Internet. This technique is an Internet marketing strategy which shows how search engines work, what people search for.

How search engine works-

Search engines perform the search operation on text data. Firstly search engine crawl the web page. Crawler or Spider is responsible to perform crawl operation. Spider crawl the search string and extract links to other web pages and return data found on the web page to indexer. Now indexer fetch information about the page. After this all the data is stored into a scheduler for crawling.

Googlebot is the spider or crawler of Google.

White Hat versus Black Hat SEO technique:- SEO technique can be organized into two major categories: White Hat and Black Hat.

White hat techniques follow the search engines' guidelines. This technique summed up content for users, not for search engines.

Black hat SEO ranks a web page in a way that are refused by search engines. When a search engine recognises a web page is using black hat technique, then web page is banned temporarily or permanently. 

 

Cloud Computing

The Cloud Computing refers to the delivery of computing services like storage, database, software, networking, server and many more by using Internet. Cloud computing provides the facilities to companies to use resources storage, an application or a virtual machine, as like utility.

Benefits of Cloud Computing:

Cloud computing provides many benefits to end users and bussinesses. Some benefits are given below-

1) Cloud computing facilitate any business firm to scalse up their business when need increases and scale down when demand decrease.

2) Cloud provider charges the users on the basis of services and resources they use.

3) End user can consume computing resources for any type of workload on demand.

Categories of Cloud Services:

Cloud computing has been divided into three broad categories, which are: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS).

1) IaaS venders offer computing infrastructure like virtual machines as a service that let the users transfer workload to a VM. Users can start, stop and configure the VM. Xen, Oracle VirtualBox, Oracle VM, VMWare etc. are the example of IaaS model.

2) PaaS venders offer a host development environment on their infrastructure to developers. The PaaS model provides a computing plateform such as web server, database, operating system etc.

3) SaaS model delivers software application over the internet; which are known as web services. SaaS is also known as "on-demand software". 

 

DoS Attack / Stress Testing

DoS attack stands for denial-of-service attack. It is also known as stress testing. It is a type of cyber attack which makes a website, machine or network resource unavailable.

DoS attack is accomplished by using flooding technique, while in a distributed denial-of-service attack, the traffic comes from many different sources. In this way DdoS attack is very difficult to stop.

In DDoS attack the perpetrators uses more than one unique IP address.

Types of DoS Attacks-

1. Amplified DNS (Domain Name System) denial-of-service attack.

2. Buffer overflow

3. PING-of-death attack down the Packet Inter-Network Groper (ping) protocol which may cause down the targeted system/server.

4. SYN flooding attack

5. Teardrop attack

US-CERT (Computer Emergency Readiness Team) suggest following points, which indicate the DoS attack-

1. Network may be down, especially when opening a file.

2. A perticular/any website is not accessible.

3. A bulk of spam emails.

Defence methods- There are many prevention and response tools are availble which are given below-

1. In application front end hardware analyzes data packets and identifies the nature of data packets.

2. Firewall is used to prevent simple DoS attack.

3. Intrusion prevention system (IPS) is used to identify the code block with bad intent.

4. DDS (DoS Defence System) based defence system data rate based attack such as SYN floods, ICMP floods and protocol attacks such as ping of death, teardrop.

When a white hat hacker used DoS attack to check vulnerability of system/server, then it is known as stress testing.

In the world of computer, stess testing is leagle, because it is used to find out the loop holes of system.

VPN (Virtual Private Network) - in Hindi

VPN

आज हम VPN (वीपीएन) के बारे में चर्चा करेगें। VPN का मतलब Virtual Private Network होता है। इसका प्रयोग कौन और क्यों करता है? उदाहरण के लिए एक छोटी कम्पनी को लेते है । शुरुआत में इसका आफिस केवल एक शहर में होता है। लेकिन जैसे-जैसे इसका मुनाफा बढ़ता जाता है इसके आफिस दूसरे शहरों में खुलने लगते है। तब कम्पनी को जरूरत पड़ती है सभी आफिस को जोड़ने की, जिससे इसका कार्य सुचारू रूप से हो सके। इसी बात के ध्यान में रखकर VPN को बनाया गया। मुख्यतः इसका उपयोग कम्पनियाँ, शैक्षिणिक संस्थान, सरकारी संगठन आदि करते है।

VPN से दूर बैठे प्रयोगकर्ता (Remote user) को एक विश्वनीय एवं सुरक्षित कनेक्शन (Connection) प्रदान किया जाता है। इस तकनीक के प्रयोग से पब्लिक इण्टरनेट (Public internet) में एक प्राइवेट नेटवर्क (Private network) बनाया जाता है। इसके लिए सभी आफिस के बीच एक टनल लिंक (tunnel link) बनायी जाती है। टनल की मदद से ही डाटा का सुरक्षित आदान-प्रदान हो पाता है। डाटा के सुरक्षित आदान-प्रदान के लिए encryption तकनीक का प्रयोग करता है।

VPN के प्रयोग से प्रतिबंधित वेबसाइट (Blocked websites) को भी चलाया जा सकता है। इस कार्य के लिए बस IP address को hide करना पड़ेगा, जो कि VPN से संभव है।

VPN को बनाने के लिए कुछ प्रोटोकाल (Protocol) इस्तेमाल होते है, जो निम्नलिखित है-

1. IP Security (IPsec)

2. PPTP (Point to Point Tunneling Protocol)

3. L2TP (Layer to Tunneling Protocol)

4. DTLS (Datagram Transport Layer Security)

5. SSTP (Secure Socket Tunneling Protocol)

6. MPPE (Microsoft Point to Point Encryption)

IPv6 (Internet Protocol version 6)

IPv6 stands for Internet Protocol version 6. IPv6 is the most recent version of Internet Protocol (IP). IPv6 belongs to Internet Layer and responsible for end-to-end communication. IPv6 was developed by the IETF (Internet Engineering Task Force). IPv6 was developed to remove the pitfalls of IPv4 (Internet Protocol version 4).

Each and every device on the Internet needs a unique IP address for identification and with the fast growth of the Internet and limited address space of IPv4, there was need to develop IPv6 to provide address space to all device on the Internet. IPv6 has 128-bit address and provides approximately 3.4×10³⁸ address space.

IPv6 provides more benefits in comparison IPv4. Device mobility, security and easy configuration have been mentioned in the design of IPv6. IPv6 provides hierarchical address allocation methods which limits the expansion of routing tables. IPv6 does not provide interoperability functions with IPv4. Direct communication between the IPv4 and IPv6 is not possible therefore IPv6 creates a parallel and independent network and by the help of translator gateways, exchanges traffic between the two networks i.e. IPv6 and IPv4.

 IPv6 addresses are written in eight groups of hexadecimal digits which are separated by colons. Example of IPv6 address is 2013:0ab8:a5a4:0000:8dbc:8450:4aa5:891c.

IPv6 uses a new packet format and minimize packet header processing by the routers. IPv6 provides more benefit in comparison with IPv4, are given below –

1. Network security

2. Stateless address which automatically configured when connected to IPv6 network

3. Large address space

4. Multicast a packet to multiple destinations in a single send command

5. Provides Privacy using globally unique IP addresses

Internet Protocol version 4 (IP Address)

An IP stands for Internet Protocol, which is a numerical label assigned to each device in a network. An IP also known as IP address. An IP address performs mainly two principal functions: network interface identification and location addressing.

An IP is a 32-bit number. These numbers are ranged from 0 to 255 and separated by dots or periods. Each part represents a group of 8 bits (octet). IP addresses may be represented in various hexadecimal, octal, or binary representation. It is also known as Internet Protocol Version 4 (IPv4). An IPv4 address is canonically represented in dot-decimal notation. IP addresses are usually written in human readable symbols, such as 192.168.75.122.

An IP address is divided in two parts: network part and host part. The highest order octet i.e. most significant bits, in an address, were known as the network identifier and the rest of the bits were known as host part and were used for host identification in a network.

For simplicity IP address is divided into 5 classes. The classes of IP address are briefly given below:

Class	Range	Leading bits	Size of network no field	Size of rest bits
A	0-127	0	8	24
B	128-191	10	16	16
C	192-223	110	24	8
D	224-239	For Multicasting	--	--
E	204-255	For Experimental purpose	--	--

The Internet Assigned Numbers Authority (IANA) is responsible for allocation of IP address space globally. There are two versions of IP address: IPv4 and IPv6. We discuss IPv6 in next blog.

Most Popular Linux OS - In Hindi

आज हम कुछ Linux OS पर चर्चा करेंगे जिनको पूरे विश्व में बहुत ज्यादा प्रयोग किया जाता है । हम जानेंगें उन Linux OS को जो सबसे ज्यादा पसंद किये जाते हैं ।

Linux Mint

आज दुनिया में Linux Mint सर्वाधिक प्रयोग किया जाने वाला और पसंद किया जाने वाला OS है । इसका अपना खुद का desktop environment है । Linux Mint में Firefox, Liber Office, GIMP इत्यादि application software पहले से install रहते है जिससे user को बाद में इन्हे install न करना पड़े । जो लोग पहली-पहल बार Linux प्रयोग करने जा रहें है उनके लिए Linux Mint सर्वोत्तम है ।

Ubuntu

Linux का यह फ्लेवर दुनिया में खूब पसंद किये जाने वाले OS में से एक है । Ubuntu ने पिछले कुछ वर्षों में काफी प्रसिद्धि (popularity) हासिल की है । आज की तारीख में Ubuntu डेस्कटॉप, लैपटॉप, स्मार्ट फोन, टैबलेट आदि डिवाइसेस के लिए उपलब्ध है । कोई भी बिना कोई पैसा चुकाए इसे प्रयोग कर सकता है । Ubuntu उनके लिए बेहतर है जो OS X और Windows को छो़ड़कर Linux को प्रयोग करना चाहते है ।

openSUSE
openSUSE एक बहुत ही प्रसिद्ध (popular) Linux distro है जो commercial और private दोनो तरह के user के लिए उपलब्ध है । यह RPM Package Management System पर आधारित है अर्थात RPM Package Management System प्रयोग करता है । openSUSE में पर्याप्त pre-installed application software मौजूद है जिससे user को कोई परेशानी न हो । जो stable और reliable साफ्टवेयर चाहते है उनके के लिए openSUSE बनाया गया है ।

Debian
पूरे विश्व में Debian सबसे पुराने और बेस्ट Linux distros  में से एक है । Debian महत्व देता है stability को, जिस कारण से जल्दी-जल्दी इसके updates नही आते है । जो security और stability को पसन्द करतें है और बार-बार साफ्टवेयर update नही करना चाहते है उनके लिए ही तो Debian बनाया गया है । 

Arch Linux
Arch Linux एक बहुत ही शक्तिशाली OS है जो कि user को कुछ भी करने की आजादी देता है । परन्तु इसके लिए Linux की अच्छी समझ होनी चाहिए जो आनलाइन वीडियो ट्यूटोरियल इत्यादि से हासिल की जा सकती है । जिनकी पकड़ Linux पर बहुत अच्छी है, Arch Linux उनके लिए ही दुनिया में लाया गया है । 

ये एक छोटा सा लेख समर्पित है हिन्दी भाषियों को ।।