TCP IP Illustrated

4708 chapter 16 bootp bootstrap protocol number of

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Unformatted text preview: by a proxy server (described in Section 16.5). The transaction ID is a 32-bit integer set by the client and returned by the server. This lets the client match a response with a request. The client should set this to a random number for each request. file:///D|/Documents%20and%20Settings/bigini/Documenti/homenet2run/tcpip/tcp-ip-illustrated/bootp.htm (2 of 9) [12/09/2001 14.47.08] Chapter 16. BOOTP: Bootstrap Protocol Number of seconds can be set by the client to the time since it started trying to bootstrap. The servers can look at this value, and perhaps a secondary server for a client won't respond until the number of seconds has exceeded some value, implying that the client's primary server is down. If the client already knows its IP address, it fills in the client IP address. Otherwise, the client sets this to 0. In the latter case the server fills in your IP address with the client's IP address. The server IP address is filled in by the server. If a proxy server is used (Section 16.5), that proxy server fills in its gateway IP address. The client must set its client hardware address. Although this is the same value as in the Ethernet header, by placing the field in the UDP datagram also, it is easily available to any user process (e.g., a BOOTP server) that receives the datagram. It is normally much harder (or impossible) for a process reading UDP datagrams to determine the fields in the Ethernet header that carried the UDP datagram. The server hostname is a null terminated string that is optionally filled in by the server. The server can also fill in the boot filename with the fully qualified, null terminated pathname of a file to bootstrap from. The vendor-specific area is used for various extensions to BOOTP. Section 16.6 describes some of these extensions. When a client is bootstrapping using BOOTP (an opcode of 1) the request is normally a linklayer broadcast and the destination IP address in the IP header is normally 255.255.255.255 (the limited broadcast. Section 12.2). The...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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