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44 lines
2.0 KiB
Plaintext
44 lines
2.0 KiB
Plaintext
Original README (from 1992)
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fping - A tool to quickly ping N number of hosts to determine
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their reachability.
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Roland J. Schemers III - Stanford University
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schemers@Stanford.EDU
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fping is a ping(1) like program which uses the Internet Control
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Message Protocol (ICMP) echo request to determine if a host is
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up. fping is different from ping in that you can specify any
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number of hosts on the command line, or specify a file containing
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the lists of hosts to ping. Instead of trying one host until it
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timeouts or replies, fping will send out a ping packet and move
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on to the next host in a round-robin fashion. If a host replies,
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it is noted and removed from the list of hosts to check. If a host
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does not respond within a certain time limit and/or retry limit it
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will be considered unreachable.
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Site
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Stanford University has a large TCP/IP network with over 16,000
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assigned IP addresses and over 100 IP subnets.
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Problem and Issues
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With a large a number of IP addresses in use, its becomes more and
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more time consuming to check on which IP addresses are actively
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in use, and which critical machines (routers, bridges, servers, etc)
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are reachable. One example is we have a program which goes through
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all of our routers arp caches looking for IP addresses that are in
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use. After finding a list of IP addresses that aren't in any arp
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caches fping can then be used to see if these IP addresses really
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aren't being used, or are just behind the routers. Checking 2500
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hosts (99% of which are unreachable) via ping can take hours.
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fping was written to solve the problem of pinging N number of hosts
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in an efficient manner. By sending out pings in a round-robin fashion
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and checking on responses as they come in at random, a large number of
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hosts can be checked at once.
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Unlike ping, fping is meant to be used in scripts and its
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output is easy to parse.
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