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Figure 28.1 |
A client and server using TCP/IP protocols to communicate across an internet. The client and server each interact with a protocol in the transport layer. |
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Figure 28.2 |
Two servers on a single computer accessed by clients on two other computers. Client 1 can access server 1, while client 2 accesses server 2. |
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Figure 3.2 |
Illustration of the API calls used for a trivial interaction. The client sends one request and receives one reply. |
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Figure 3.5 |
Illustration of the echo application, which can be used on any two computers connected to the Internet. The client program runs on one computer and the server program runs on another. |
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Figure 30.1 |
The sequence of socket procedure calls in the example client and server. The server must call listen before a client calls connect. |
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Figure 32.3 |
The path of an e-mail message. The mail transfer program on the sender's computer becomes a client of the remote mail server. |
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Figure 32.4 |
An example SMTP transfer between a client on computer example.com and a server on computer foobar.com. Each line is labeled to show whether the client or server transmits the line. |
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Figure 32.7 |
The path of e-mail when POP is used to access a mailbox. The mail can arrive from the sender's computer or a mail gateway. To retrieve messages from the mailbox, a user runs a program that becomes a client of the POP server. |
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Figure 34.2 |
TCP connections between an FTP client and server during a file transfer, with an arrow showing the direction in which each connection was formed. Although the control connection remains open, the data connection is closed after the transfer completes. |
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Figure 35.5 |
Major components of a Web browser. Dark arrows show the flow of data; other arrows show control paths. The data paths from clients to interpreters are not shown. |
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Figure 38.2 |
The example program from Figure 38.1 divided into a client and a server. |
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Figure 31.3 |
Two examples of ways the domain name hierarchy from Figure 31.2 can be divided among three servers. Each organization chooses how to divide names among its servers. |
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Figure 32.6 |
The path of a message as it passes from a sender's interface through a mail gateway. On the gateway computer, an exploder handles incoming e-mail, and a conventional mail transfer program sends a copy to each recipient. |
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Figure 35.4 |
Example HTTP header returned by a server. The status code 200 on the first line indicates that the server honored the request; additional lines give further information about the requested item. |
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Data file 2 |
Anonymous FTP session with dir, get and put |
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Data file 3 |
Anonymous FTP session using mput |
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Data file 4 |
Anonymous FTP session using mget |
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Data file 5 |
TELNET session |
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Data file 6 |
SMTP session with delivery of one mail message |
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Data file 7 |
WWW browser session |
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Data file 8 |
X Window System application protocol messages from several clients |
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Code sample 30_1 |
Code sample for client in section 30.6 |
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Code sample 30_2 |
Code sample for server in section 30.7 |
