The sockets interface was designed in the early 1980s

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Unformatted text preview: NET unnamed root 615 mil edu gov com first-level domain names mit cmu berkeley amazon second-level domain names cs ece www 208.216.181.15 third-level domain names cmcl pdl kittyhawk 128.2.194.242 imperial 128.2.189.40 Figure 12.10: Subset of the Internet domain name hierarchy. The Internet defines a mapping between the set of domain names and the set of IP addresses. Until 1988, this mapping was maintained manually in a single text file called hosts.txt. Since then, the mapping has been maintained in a distributed world-wide database known as DNS (Domain Naming System). The DNS database consists of millions of the host entry structures shown in Figure 12.11, each of which defines the mapping between a set of domain names (an official name and a list of aliases) and a set of IP addresses. In a mathematical sense, we can think of each host entry as an equivalence class of domain names and IP addresses. netdb.h /* DNS host entry structure */ struct hostent { char *h_name; /* official domain name o...
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This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.

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