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1 =head1 NAME
2
3 fping - send ICMP ECHO_REQUEST packets to network hosts
4
5 =head1 SYNOPSIS
6
7 B<fping> [ I<options> ] [ I<systems...> ]
8
9 =head1 DESCRIPTION
10
11 B<fping> is a program like B<ping> which uses the Internet Control Message
12 Protocol (ICMP) echo request to determine if a target host is responding.
13 B<fping> differs from B<ping> in that you can specify any number of targets on the
14 command line, or specify a file containing the lists of targets to ping.
15 Instead of sending to one target until it times out or replies, B<fping> will
16 send out a ping packet and move on to the next target in a round-robin fashion.
17 In the default mode, if a target replies, it is noted and removed from the list
18 of targets to check; if a target does not respond within a certain time limit
19 and/or retry limit it is designated as unreachable. B<fping> also supports
20 sending a specified number of pings to a target, or looping indefinitely (as in
21 B<ping> ). Unlike B<ping>, B<fping> is meant to be used in scripts, so its
22 output is designed to be easy to parse. Current statistics can be obtained without
23 termination of process with signal SIGQUIT (^\ from the keyboard on most systems).
24
25 =head1 OPTIONS
26
27 =over 5
28
29 =item B<-4>, B<--ipv4>
30
31 Restrict name resolution and IPs to IPv4 addresses.
32
33 =item B<-6>, B<--ipv6>
34
35 Restrict name resolution and IPs to IPv6 addresses.
36
37 =item B<-a>, B<--alive>
38
39 Show systems that are alive.
40
41 =item B<-A>, B<--addr>
42
43 Display targets by address rather than DNS name. Combined with -d, the output
44 will be both the ip and (if available) the hostname.
45
46 =item B<-b>, B<--size>=I<BYTES>
47
48 Number of bytes of ping data to send. The minimum size (normally 12) allows
49 room for the data that B<fping> needs to do its work (sequence number,
50 timestamp). The reported received data size includes the IP header (normally
51 20 bytes) and ICMP header (8 bytes), so the minimum total size is 40 bytes.
52 Default is 56, as in B<ping>. Maximum is the theoretical maximum IP datagram
53 size (64K), though most systems limit this to a smaller, system-dependent
54 number.
55
56 =item B<-B>, B<--backoff>=I<N>
57
58 Backoff factor. In the default mode, B<fping> sends several requests to a
59 target before giving up, waiting longer for a reply on each successive request.
60 This parameter is the value by which the wait time (B<-t>) is multiplied on each
61 successive request; it must be entered as a floating-point number (x.y). The
62 default is 1.5.
63
64 =item B<-c>, B<--count>=I<N>
65
66 Number of request packets to send to each target. In this mode, a line is
67 displayed for each received response (this can suppressed with B<-q> or B<-Q>).
68 Also, statistics about responses for each target are displayed when all
69 requests have been sent (or when interrupted).
70
71 =item B<-C>, B<--vcount>=I<N>
72
73 Similar to B<-c>, but the per-target statistics are displayed in a format
74 designed for automated response-time statistics gathering. For example:
75
76 $ fping -C 5 -q somehost
77 somehost : 91.7 37.0 29.2 - 36.8
78
79 shows the response time in milliseconds for each of the five requests, with the
80 C<-> indicating that no response was received to the fourth request.
81
82 =item B<-d>, B<--rdns>
83
84 Use DNS to lookup address of ping target. This allows you to give fping
85 a list of IP addresses as input and print hostnames in the output. This is similar
86 to option B<-n>/B<--name>, but will force a reverse-DNS lookup even if you give
87 hostnames as target (NAME->IP->NAME).
88
89 =item B<-D>, B<--timestamp>
90
91 Add Unix timestamps in front of output lines generated with in looping or counting
92 modes (B<-l>, B<-c>, or B<-C>).
93
94 =item B<-e>, B<--elapsed>
95
96 Show elapsed (round-trip) time of packets.
97
98 =item B<-f>, B<--file>
99
100 Read list of targets from a file. This option can only be used by the root
101 user. Regular users should pipe in the file via stdin:
102
103 $ fping < targets_file
104
105 =item B<-g>, B<--generate> I<addr/mask>
106
107 Generate a target list from a supplied IP netmask, or a starting and ending IP.
108 Specify the netmask or start/end in the targets portion of the command line. If
109 a network with netmask is given, the network and broadcast addresses will be
110 excluded. ex. To ping the network 192.168.1.0/24, the specified command line
111 could look like either:
112
113 $ fping -g 192.168.1.0/24
114
115 or
116
117 $ fping -g 192.168.1.1 192.168.1.254
118
119 =item B<-h>, B<--help>
120
121 Print usage message.
122
123 =item B<-H>, B<--ttl>=I<N>
124
125 Set the IP TTL field (time to live hops).
126
127 =item B<-i>, B<--interval>=I<MSEC>
128
129 The minimum amount of time (in milliseconds) between sending a ping packet
130 to any target (default is 10, minimum is 1).
131
132 =item B<-I>, B<--iface>=I<IFACE>
133
134 Set the interface (requires SO_BINDTODEVICE support).
135
136 =item B<-l>, B<--loop>
137
138 Loop sending packets to each target indefinitely. Can be interrupted with
139 Ctrl-C; statistics about responses for each target are then displayed.
140
141 =item B<-m>, B<--all>
142
143 Send pings to each of a target host's multiple IP addresses (use of option '-A'
144 is recommended).
145
146 =item B<-M>, B<--dontfrag>
147
148 Set the "Don't Fragment" bit in the IP header (used to determine/test the MTU).
149
150 =item B<-n>, B<--name>
151
152 If targets are specified as IP addresses, do a reverse-DNS lookup on them
153 to print hostnames in the output.
154
155 =item B<-N>, B<--netdata>
156
157 Format output for netdata (-l -Q are required). See: L<http://my-netdata.io/>
158
159 =item B<-o>, B<--outage>
160
161 Calculate "outage time" based on the number of lost pings and the interval used (useful for network convergence tests).
162
163 =item B<-O>, B<--tos>=I<N>
164
165 Set the typ of service flag (TOS). I<N> can be either decimal or hexadecimal
166 (0xh) format.
167
168 =item B<-p>, B<--period>=I<MSEC>
169
170 In looping or counting modes (B<-l>, B<-c>, or B<-C>), this parameter sets
171 the time in milliseconds that B<fping> waits between successive packets to
172 an individual target. Default is 1000 and minimum is 10.
173
174 =item B<-q>, B<--quiet>
175
176 Quiet. Don't show per-probe results, but only the final summary. Also don't
177 show ICMP error messages.
178
179 =item B<-Q>, B<--squiet>=I<SECS>
180
181 Like B<-q>, but additionally show interval summary results every I<SECS>
182 seconds.
183
184 =item B<-r>, B<--retry>=I<N>
185
186 Retry limit (default 3). This is the number of times an attempt at pinging
187 a target will be made, not including the first try.
188
189 =item B<-R>, B<--random>
190
191 Instead of using all-zeros as the packet data, generate random bytes.
192 Use to defeat, e.g., link data compression.
193
194 =item B<-s>, B<--stats>
195
196 Print cumulative statistics upon exit.
197
198 =item B<-S>, B<--src>=I<addr>
199
200 Set source address.
201
202 =item B<-t>, B<--timeout>=I<MSEC>
203
204 Initial target timeout in milliseconds. In the default, non-loop mode, the
205 default timeout is 500ms, and it represents the amount of time that B<fping>
206 waits for a response to its first request. Successive timeouts are multiplied
207 by the backoff factor specified with B<-B>.
208
209 In loop/count mode, the default timeout is automatically adjusted to match
210 the "period" value (but not more than 2000ms). You can still adjust the timeout
211 value with this option, if you wish to, but note that setting a value larger
212 than "period" produces inconsistent results, because the timeout value can
213 be respected only for the last ping.
214
215 Also note that any received replies that are larger than the timeout value, will
216 be discarded.
217
218 =item B<-T> I<n>
219
220 Ignored (for compatibility with fping 2.4).
221
222 =item B<-u>, B<--unreach>
223
224 Show targets that are unreachable.
225
226 =item B<-v>, B<--version>
227
228 Print B<fping> version information.
229
230 =item B<-x>, B<--reachable>=I<N>
231
232 Given a list of hosts, this mode checks if number of reachable hosts is >= N
233 and exits true in that case.
234
235 =back
236
237 =head1 EXAMPLES
238
239 Generate 20 pings to two hosts in ca. 1 second (i.e. one ping every 50 ms to
240 each host), and report every ping RTT at the end:
241
242 $ fping --quiet --interval=1 --vcount=20 --period=50 127.0.0.1 127.0.0.2
243
244 =head1 AUTHORS
245
246 =over 4
247
248 =item *
249
250 Roland J. Schemers III, Stanford University, concept and versions 1.x
251
252 =item *
253
254 RL "Bob" Morgan, Stanford University, versions 2.x
255
256 =item *
257
258 David Papp, versions 2.3x and up
259
260 =item *
261
262 David Schweikert, versions 3.0 and up
263
264 =back
265
266 B<fping website: L<http://www.fping.org>>
267
268 =head1 DIAGNOSTICS
269
270 Exit status is 0 if all the hosts are reachable, 1 if some hosts
271 were unreachable, 2 if any IP addresses were not found, 3 for invalid command
272 line arguments, and 4 for a system call failure.
273
274 =head1 RESTRICTIONS
275
276 If fping was configured with C<--enable-safe-limits>, the following values are
277 not allowed for non-root users:
278
279 =over 4
280
281 =item *
282
283 B<-i> I<n>, where I<n> < 1 msec
284
285 =item *
286
287 B<-p> I<n>, where I<n> < 10 msec
288
289 =back
290
291 =head1 SEE ALSO
292
293 C<ping(8)>