Cisco PIX 520 - PIX Firewall 520, Онлайн руководство пользователя

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The Internet protocols consist of a suite of communication protocols, of which the two best known are the
Transmission Control Protocol (TCP) and the Internet Protocol (IP). The Internet protocol suite not only includes
lower-layer protocols (such as TCP and IP), but it also specifies common applications such as electronic mail,
terminal emulation, and file transfer.
Internet Protocols Application-Layer Protocols
The Internet protocol suite includes many application-layer protocols that represent a wide variety of applications,
including the following:
File Transfer Protocol (FTP)—Moves files between devices
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Simple Network-Management Protocol (SNMP)—Primarily reports anomalous network conditions and
sets network threshold values
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Telnet—Serves as a terminal emulation protocol
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X Windows—Serves as a distributed windowing and graphics system used for communication between X
terminals and UNIX workstations
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Network File System (NFS)—External Data Representation (XDR), and Remote Procedure Call
(RPC)—Work together to enable transparent access to remotenetwork resources
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Simple Mail Transfer Protocol (SMTP)—Provides electronic mail services
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Domain Name System (DNS)—Translates the names of network nodes into network addresses
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Layers
Internet protocols span the complete range of OSI model layers which describe the function of network
protocols..