What is Web crawler?

A web crawler (also known as a web spider or web robot) is a program or automated script which browses the World Wide Web in a methodical, automated manner.

This process is called Web crawling or spidering.

Many legitimate sites, in particular search engines, use spidering as a means of providing up-to-date data.

Web crawlers are mainly used to create a copy of all the visited pages for later processing by a search engine, that will index the downloaded pages to provide fast searches.

Crawlers can also be used for automating maintenance tasks on a Web site, such as checking links or validating HTML code.

Also, crawlers can be used to gather specific types of information from Web pages, such as harvesting e-mail addresses (usually for spam).
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How to Connect Two Computers Via Crossover Ethernet Cable?

In this tutorial we are going to show you how to transfer data from one computer to another. We need to PC/Laptop and a crossover cable to transfer data. PC 1 Step1: Go to “Open Networking and Sharing Center“. Step2: Click on “Local Area Connection“. Step3: Now click on “Properties“. Step4: Double click on “Internet Protocol Version 4(TCP/IPv6)“. Step5: Click on “Use the following IP address:” and enter the IP address: as 192.168.1.1 and just give a click onSubnet mask. Once done click “Ok” and close it. PC 2 Step1: Go to “Open Networking and Sharing Center“. Step2: Click on “Local Area Connection“. Step3: Now click on “Properties“. Step4: Double click on “Internet Protocol Version 4(TCP/IPv6)“. Step5: Click on “Use the following IP address:” and enter the IP address: as 192.168.1.2 and just give a click onSubnet mask. Once done click “Ok” and close it. Now two computers are connected. To share files we need to give access to our drives, so follow the c

What is Port (computer networking)

In the internet protocol suite, a port is an endpoint of communication in an operating system. While the term is also used for female connectors on hardware devices (see computer port), in software it is a logical construct that identifies a specific process or a type of network service. A port is always associated with an IP address of a host and the protocol type of the communication, and thus completes the destination or origination network address of a communication session. A port is identified for each address and protocol by a 16-bit number, commonly known as the port number. For example, an address may be 'protocol: TCP, IP address: 1.2.3.4, port number: 80', which may be written 1.2.3.4:80 when the protocol is known from context. Specific port numbers are often used to identify specific services. _________________________

Denial of service (DoS) attack Trojans

These Trojans give the attacker the power to start a distributed denial of service (DDoS) attack if there are enough victims. The main idea is that if you have 200 infected ADSL users and you attack the victim simultaneously from each, this will generate HEAVY traffic (more than the victim's bandwidth can carry, in most cases), causing its access to the Internet to shut down. WinTrinoo is a DDoS tool that has recently become very popular; through it, An attacker who has infected many ADSL users can cause major Internet sites to shut down; Early examples of this date back to February 2000, when a number of prominent e-commerce sites such as Amazon, CNN, E*Trade, Yahoo and eBay were attacked. Another variation of a DoS Trojan is the mail-bomb Trojan, where the main aim is to infect as many machines as possible and simultaneously attack specific email address/addresses with random subjects and contents that cannot be filtered. Again, a DoS Trojan is similar to a virus,

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