tailieunhanh - Microsoft Press windows server 2008 tcp ip protocols and services phần 10

Một lĩnh vực chiều dài thay đổi có chứa các tính ICV của người gửi. Trong Windows Server 2008 và Windows Vista, đây là tin nhắn xác thực dựa trên mã băm Message Digest 5 (MD5) hoặc Secure Hash thuật toán HMAC 1 (SHA1) khóa giá trị hash (HMAC). Các lĩnh vực dữ liệu xác thực cung cấp xác thực nguồn gốc dữ liệu | 426 Windows Server 2008 TCP IP Protocols and Services information on IP multicast addresses see the section IP Multicast Addresses later in this appendix. Windows Server 2008 and Windows Vista support class D addresses for IP multicast traffic. Class E Class E addresses are experimental addresses reserved for future use. The five high-order bits in a class E address are set to 11110. Windows Server 2008 and Windows Vista do not support the use of class E addresses. Rules for Enumerating Address Prefixes When enumerating IP address prefixes the following rules apply The address prefix cannot begin with 127 as the first octet All addresses are reserved as loopback addresses. All the bits in the address prefix cannot be set to 1 Address prefixes set to all 1s are reserved for broadcast addresses. All the bits in the address prefix cannot be set to 0 Address prefixes set to all 0s are reserved for indicating a host on the local network. The address prefix must be unique to the IP internetwork. Table A-1 lists the ranges of address prefixes based on the IP address classes. Class-based address prefixes are expressed by setting all host bits to 0 and expressing the result in dotted decimal notation. Table A-1 Address Class Ranges of Address Prefixes Address Class First Address Prefix Last Address Prefix Number of Networks Class A 126 Class B 16 384 Class C 2 097 152 Note IP address prefixes even though expressed in dotted decimal notation are not IP addresses assigned to network interfaces. Rules for Enumerating Usable Host IDs When enumerating usable IP host IDs the following rules apply All bits in the host ID cannot be set to 1 Host IDs set to all 1s are reserved for broadcast addresses. All the bits in the host ID cannot be set to 0 Host IDs set to all 0s are reserved for the expression of IP address prefixes. The host ID must be unique to the network. Appendix A Internet Protocol IP Addressing