On the Internet, computers are identified by IP addresses. During communication, computers will open different ports for communication, such as port 21 for ftp service, port 80 for http service, and port 110 for POP3 service. These ports will be used when we are downloading files, browsing web pages and using email services respectively.

When there are loopholes in the operating system or in the application software, hackers can make use of these loopholes to hack into our computers. They will install a Trojan horse program on the computer. This program will open certain ports so that hackers can get control of the computer. To protect the computer from unauthorized access, install firewalls to close the ports which are not being used.

If there is unauthorized access through certain ports, messages sent by the hacker will be stopped by the firewall to shut down the hacking activities.
 
On the Internet, computers are identified by IP addresses. During communication, computers will open different ports for communication, such as port 21 for ftp service, port 80 for http service, and port 110 for POP3 service. These ports will be used when we are downloading files, browsing web pages and using email services respectively.

When there are loopholes in the operating system or in the application software, hackers can make use of these loopholes to hack into our computers. They will install a Trojan horse program on the computer. This program will open certain ports so that hackers can get control of the computer. To protect the computer from unauthorized access, install firewalls to close the ports which are not being used.

If there is unauthorized access through certain ports, messages sent by the hacker will be stopped by the firewall to shut down the hacking activities.
 
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Duration:
On the Internet, computers are identified by IP addresses. During communication, computers will open different ports for communication, such as port 21 for ftp service, port 80 for http service, and port 110 for POP3 service. These ports will be used when we are downloading files, browsing web pages and using email services respectively.

When there are loopholes in the operating system or in the application software, hackers can make use of these loopholes to hack into our computers. They will install a Trojan horse program on the computer. This program will open certain ports so that hackers can get control of the computer. To protect the computer from unauthorized access, install firewalls to close the ports which are not being used.

If there is unauthorized access through certain ports, messages sent by the hacker will be stopped by the firewall to shut down the hacking activities.
 
Level:
Duration: