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54 lines
2.4 KiB
54 lines
2.4 KiB
18 years ago
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ping The ping command ��bounces�� a packet to and from a specified network host.
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Format The format for this command is:
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ping [-nqv] [-i wait]] [-s size] [-l preload] host
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where:
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-i wait Wait waitseconds between sending each packet. The default is
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to wait for one second between each packet.
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-l preload If preload is specified, ping sends that many packets as fast as
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possible before falling into its normal mode of behavior.
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-n Numeric output only. No attempt will be made to lookup symbolic
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names for host addresses.
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-q Quiet output. Nothing is displayed except the summary lines at
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startup time and when finished.
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-s size Specifies the number of data bytes to be sent. The default is 56,
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which translates into 64 ICMP data bytes when combined with
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the 8 bytes of ICMP header data.
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-v Verbose output. ICMP packets other than ECHO_RESPONSE
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that are received are listed. ��Echo Replies�� are displayed symbolically.
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Functional
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Description
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The ping command is used to verify ether net network connections and
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setup. It makes use of a feature of the ��ICMP�� protocol, which is used by
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hosts and gateways for low-level administrative chores. Each ICMP host is
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required to respond to an ECHO_REQUEST datagram with an
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ECHO_RESPONSE. ECHO_REQUEST datagrams (��pings��) have an IP and
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ICMP header, followed by a time and then an arbitrary number of ��pad�� bytes
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used to fill out the packet. The command continues pinging until interrupted
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by a Control-C.
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When using ping for fault isolation, start by pinging ��127.0.0.1�� (a universal
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self-address, by internet convention.) This verifies that at least the onboard
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setup is workable. Then, hosts and gateways further and further away should
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be ��pinged��. Round-trip times and packet loss statistics are computed. If
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duplicate packets are received, they are not included in the packet loss calculation,
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although the round trip time of these packets is used in calculating the
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minimum/average/maximum round-trip time numbers. When the program is
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terminated by a Control-C a brief summary is displayed.
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Ping will report duplicate and damaged packets. Duplicate packets ��should
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never happen��: they�d have to be gateway problems. Tell your network manager.
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Damaged packets (data doesn�t look like it should) are serious cause for
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alarm and often indicate broken hardware somewhere in the ping packet�s
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path (in the network or in the hosts).
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