tailieunhanh - e mail virus protection handbook phần 2

Cho bạn biết địa chỉ IP và / hoặc giải quyết địa chỉ IP của các hacker tấn công hệ thống của bạn. Lọc ra các gói tin TCP / IP có liên quan đến. Ví dụ, phần mềm tường lửa cá nhân có thể chặn các gói dữ liệu được gửi bởi ứng dụng ping. Vô hiệu hoá một hệ thống gửi và / hoặc nhận e-mail. | 24 Chapter 1 Understanding the Threats Figure shows Norton SystemWorks a typical application that contains an antivirus component. Personal firewall software often includes an anti-virus scanner. However a personal firewall takes the extra step of protecting your computer by closing down unnecessary ports. Personal firewall software can also Tell you the IP address and or resolved IP address of the hacker attacking your system. Filter out TCP IP-related packets. For example personal firewall software can block packets sent by the ping application. Disable a system from sending and or receiving e-mail. A personal firewall can provide additional services depending upon the personal firewall vendor you select. Figure Norton SystemWorks. Encryption The chief way to protect an e-mail message on the client side is to use encryption. Using encryption makes it difficult for unauthorized users to read or tamper with your e-mail. There are three types of encryption used to secure information on the Internet 1. Private key encryption The use of one password to encrypt and decrypt information. Understanding the Threats Chapter 1 25 2. Public key encryption The use of a key pair to encrypt and decrypt information. 3. Hash encryption A process that creates a numerically related hash of the information. This code is theoretically irreversible and is used to help ensure a document has not been tampered with. One of the most common ways to encrypt a document is to use a single string of text to encrypt it. If you have ever used Microsoft Word for example to encrypt a document you have used private key encryption. This form of encryption is called private key because you must take measures to ensure that your password remains secret. If an unauthorized user were to learn the password to this document then he or she would be able to open it. Let s say that you have encrypted a Microsoft Word document that you wish to give to a friend. Suppose that for some .