1Net::Ping(3) User Contributed Perl Documentation Net::Ping(3)
2
6 Net::Ping - check a remote host for reachability
7
9 use Net::Ping;
10 my $p = Net::Ping->new();
12 print "$host is alive.\n" if $p->ping($host);
13 $p->close();
14 my $p = Net::Ping->new("icmp");
16 $p->bind($my_addr); # Specify source interface of pings
17 foreach my $host (@host_array)
18 {
19 print "$host is ";
20 print "NOT " unless $p->ping($host, 2);
21 print "reachable.\n";
22 sleep(1);
23 }
24 $p->close();
25 my $p = Net::Ping->new("icmpv6");
27 my $ip = "[fd00:dead:beef::4e]";
28 print "$ip is alive.\n" if $p->ping($ip);
29 my $p = Net::Ping->new("tcp", 2);
31 # Try connecting to the www port instead of the echo port
32 $p->port_number(scalar(getservbyname("http", "tcp")));
33 while ($stop_time > time())
34 {
35 print "$host not reachable ", scalar(localtime()), "\n"
36 unless $p->ping($host);
37 sleep(300);
38 }
39 undef($p);
40 # Like tcp protocol, but with many hosts
42 my $p = Net::Ping->new("syn");
43 $p->port_number(getservbyname("http", "tcp"));
44 foreach my $host (@host_array) {
45 $p->ping($host);
46 }
47 while (my ($host, $rtt, $ip) = $p->ack) {
48 print "HOST: $host [$ip] ACKed in $rtt seconds.\n";
49 }
50 # High precision syntax (requires Time::HiRes)
52 my $p = Net::Ping->new();
53 $p->hires();
54 my ($ret, $duration, $ip) = $p->ping($host, 5.5);
55 printf("$host [ip: $ip] is alive (packet return time: %.2f ms)\n",
56 1000 * $duration)
57 if $ret;
58 $p->close();
59 # For backward compatibility
61 print "$host is alive.\n" if pingecho($host);
62
64 This module contains methods to test the reachability of remote hosts
65 on a network. A ping object is first created with optional parameters,
66 a variable number of hosts may be pinged multiple times and then the
67 connection is closed.
68 You may choose one of six different protocols to use for the ping. The
70 "tcp" protocol is the default. Note that a live remote host may still
71 fail to be pingable by one or more of these protocols. For example,
72 www.microsoft.com is generally alive but not "icmp" pingable.
73 With the "tcp" protocol the ping() method attempts to establish a
75 connection to the remote host's echo port. If the connection is
76 successfully established, the remote host is considered reachable. No
77 data is actually echoed. This protocol does not require any special
78 privileges but has higher overhead than the "udp" and "icmp" protocols.
79 Specifying the "udp" protocol causes the ping() method to send a udp
81 packet to the remote host's echo port. If the echoed packet is
82 received from the remote host and the received packet contains the same
83 data as the packet that was sent, the remote host is considered
84 reachable. This protocol does not require any special privileges. It
85 should be borne in mind that, for a udp ping, a host will be reported
86 as unreachable if it is not running the appropriate echo service. For
87 Unix-like systems see inetd(8) for more information.
88 If the "icmp" protocol is specified, the ping() method sends an icmp
90 echo message to the remote host, which is what the UNIX ping program
91 does. If the echoed message is received from the remote host and the
92 echoed information is correct, the remote host is considered reachable.
93 Specifying the "icmp" protocol requires that the program be run as root
94 or that the program be setuid to root.
95 If the "external" protocol is specified, the ping() method attempts to
97 use the "Net::Ping::External" module to ping the remote host.
98 "Net::Ping::External" interfaces with your system's default "ping"
99 utility to perform the ping, and generally produces relatively accurate
100 results. If "Net::Ping::External" if not installed on your system,
101 specifying the "external" protocol will result in an error.
102 If the "syn" protocol is specified, the "ping" method will only send a
104 TCP SYN packet to the remote host then immediately return. If the syn
105 packet was sent successfully, it will return a true value, otherwise it
106 will return false. NOTE: Unlike the other protocols, the return value
107 does NOT determine if the remote host is alive or not since the full
108 TCP three-way handshake may not have completed yet. The remote host is
109 only considered reachable if it receives a TCP ACK within the timeout
110 specified. To begin waiting for the ACK packets, use the "ack" method
111 as explained below. Use the "syn" protocol instead the "tcp" protocol
112 to determine reachability of multiple destinations simultaneously by
113 sending parallel TCP SYN packets. It will not block while testing each
114 remote host. This protocol does not require any special privileges.
115 Functions
117 Net::Ping->new([proto, timeout, bytes, device, tos, ttl, family, host,
118 port, bind, gateway, retrans, pingstring, source_verify econnrefused
119 dontfrag IPV6_USE_MIN_MTU IPV6_RECVPATHMTU])
120 Create a new ping object. All of the parameters are optional and
121 can be passed as hash ref. All options besides the first 7 must be
122 passed as hash ref.
123 "proto" specifies the protocol to use when doing a ping. The
125 current choices are "tcp", "udp", "icmp", "icmpv6", "stream",
126 "syn", or "external". The default is "tcp".
127 If a "timeout" in seconds is provided, it is used when a timeout is
129 not given to the ping() method (below). The timeout must be
130 greater than 0 and the default, if not specified, is 5 seconds.
131 If the number of data bytes ("bytes") is given, that many data
133 bytes are included in the ping packet sent to the remote host. The
134 number of data bytes is ignored if the protocol is "tcp". The
135 minimum (and default) number of data bytes is 1 if the protocol is
136 "udp" and 0 otherwise. The maximum number of data bytes that can
137 be specified is 65535, but staying below the MTU (1472 bytes for
138 ICMP) is recommended. Many small devices cannot deal with
139 fragmented ICMP packets.
140 If "device" is given, this device is used to bind the source
142 endpoint before sending the ping packet. I believe this only works
143 with superuser privileges and with udp and icmp protocols at this
144 time.
145 If <tos> is given, this ToS is configured into the socket.
147 For icmp, "ttl" can be specified to set the TTL of the outgoing
149 packet.
150 Valid "family" values for IPv4:
152 4, v4, ip4, ipv4, AF_INET (constant)
154 Valid "family" values for IPv6:
156 6, v6, ip6, ipv6, AF_INET6 (constant)
158 The "host" argument implicitly specifies the family if the family
160 argument is not given.
161 The "port" argument is only valid for a udp, tcp or stream ping,
163 and will not do what you think it does. ping returns true when we
164 get a "Connection refused"! The default is the echo port.
165 The "bind" argument specifies the local_addr to bind to. By
167 specifying a bind argument you don't need the bind method.
168 The "gateway" argument is only valid for IPv6, and requires a IPv6
170 address.
171 The "retrans" argument the exponential backoff rate, default 1.2.
173 It matches the $def_factor global.
174 The "dontfrag" argument sets the IP_DONTFRAG bit, but note that
176 IP_DONTFRAG is not yet defined by Socket, and not available on many
177 systems. Then it is ignored. On linux it also sets IP_MTU_DISCOVER
178 to IP_PMTUDISC_DO but need we don't chunk oversized packets. You
179 need to set $data_size manually.
180 $p->ping($host [, $timeout [, $family]]);
182 Ping the remote host and wait for a response. $host can be either
183 the hostname or the IP number of the remote host. The optional
184 timeout must be greater than 0 seconds and defaults to whatever was
185 specified when the ping object was created. Returns a success
186 flag. If the hostname cannot be found or there is a problem with
187 the IP number, the success flag returned will be undef. Otherwise,
188 the success flag will be 1 if the host is reachable and 0 if it is
189 not. For most practical purposes, undef and 0 and can be treated
190 as the same case. In array context, the elapsed time as well as
191 the string form of the ip the host resolved to are also returned.
192 The elapsed time value will be a float, as returned by the
193 Time::HiRes::time() function, if hires() has been previously
194 called, otherwise it is returned as an integer.
195 $p->source_verify( { 0 | 1 } );
197 Allows source endpoint verification to be enabled or disabled.
198 This is useful for those remote destinations with multiples
199 interfaces where the response may not originate from the same
200 endpoint that the original destination endpoint was sent to. This
201 only affects udp and icmp protocol pings.
202 This is enabled by default.
204 $p->service_check( { 0 | 1 } );
206 Set whether or not the connect behavior should enforce remote
207 service availability as well as reachability. Normally, if the
208 remote server reported ECONNREFUSED, it must have been reachable
209 because of the status packet that it reported. With this option
210 enabled, the full three-way tcp handshake must have been
211 established successfully before it will claim it is reachable.
212 NOTE: It still does nothing more than connect and disconnect. It
213 does not speak any protocol (i.e., HTTP or FTP) to ensure the
214 remote server is sane in any way. The remote server CPU could be
215 grinding to a halt and unresponsive to any clients connecting, but
216 if the kernel throws the ACK packet, it is considered alive anyway.
217 To really determine if the server is responding well would be
218 application specific and is beyond the scope of Net::Ping. For udp
219 protocol, enabling this option demands that the remote server
220 replies with the same udp data that it was sent as defined by the
221 udp echo service.
222 This affects the "udp", "tcp", and "syn" protocols.
224 This is disabled by default.
226 $p->tcp_service_check( { 0 | 1 } );
228 Deprecated method, but does the same as service_check() method.
229 $p->hires( { 0 | 1 } );
231 With 1 causes this module to use Time::HiRes module, allowing
232 milliseconds to be returned by subsequent calls to ping().
233 $p->time
235 The current time, hires or not.
236 $p->socket_blocking_mode( $fh, $mode );
238 Sets or clears the O_NONBLOCK flag on a file handle.
239 $p->IPV6_USE_MIN_MTU
241 With argument sets the option. Without returns the option value.
242 $p->IPV6_RECVPATHMTU
244 Notify an according IPv6 MTU.
245 With argument sets the option. Without returns the option value.
247 $p->IPV6_HOPLIMIT
249 With argument sets the option. Without returns the option value.
250 $p->IPV6_REACHCONF NYI
252 Sets ipv6 reachability IPV6_REACHCONF was removed in RFC3542. ping6
253 -R supports it. IPV6_REACHCONF requires root/admin permissions.
254 With argument sets the option. Without returns the option value.
256 Not yet implemented.
258 $p->bind($local_addr);
260 Sets the source address from which pings will be sent. This must
261 be the address of one of the interfaces on the local host.
262 $local_addr may be specified as a hostname or as a text IP address
263 such as "192.168.1.1".
264 If the protocol is set to "tcp", this method may be called any
266 number of times, and each call to the ping() method (below) will
267 use the most recent $local_addr. If the protocol is "icmp" or
268 "udp", then bind() must be called at most once per object, and (if
269 it is called at all) must be called before the first call to ping()
270 for that object.
271 The bind() call can be omitted when specifying the "bind" option to
273 new().
274 $p->message_type([$ping_type]);
276 When you are using the "icmp" protocol, this call permit to change
277 the message type to 'echo' or 'timestamp' (only for IPv4, see RFC
278 792).
279 Without argument, it returns the currently used icmp protocol
281 message type. By default, it returns 'echo'.
282 $p->open($host);
284 When you are using the "stream" protocol, this call pre-opens the
285 tcp socket. It's only necessary to do this if you want to provide
286 a different timeout when creating the connection, or remove the
287 overhead of establishing the connection from the first ping. If
288 you don't call open(), the connection is automatically opened the
289 first time ping() is called. This call simply does nothing if you
290 are using any protocol other than stream.
291 The $host argument can be omitted when specifying the "host" option
293 to new().
294 $p->ack( [ $host ] );
296 When using the "syn" protocol, use this method to determine the
297 reachability of the remote host. This method is meant to be called
298 up to as many times as ping() was called. Each call returns the
299 host (as passed to ping()) that came back with the TCP ACK. The
300 order in which the hosts are returned may not necessarily be the
301 same order in which they were SYN queued using the ping() method.
302 If the timeout is reached before the TCP ACK is received, or if the
303 remote host is not listening on the port attempted, then the TCP
304 connection will not be established and ack() will return undef. In
305 list context, the host, the ack time, the dotted ip string, and the
306 port number will be returned instead of just the host. If the
307 optional $host argument is specified, the return value will be
308 pertaining to that host only. This call simply does nothing if you
309 are using any protocol other than "syn".
310 When "new" had a host option, this host will be used. Without
312 $host argument, all hosts are scanned.
313 $p->nack( $failed_ack_host );
315 The reason that "host $failed_ack_host" did not receive a valid
316 ACK. Useful to find out why when ack($fail_ack_host) returns a
317 false value.
318 $p->ack_unfork($host)
320 The variant called by "ack" with the "syn" protocol and
321 $syn_forking enabled.
322 $p->ping_icmp([$host, $timeout, $family])
324 The "ping" method used with the icmp protocol.
325 $p->ping_icmpv6([$host, $timeout, $family])
327 The "ping" method used with the icmpv6 protocol.
328 $p->ping_stream([$host, $timeout, $family])
330 The "ping" method used with the stream protocol.
331 Perform a stream ping. If the tcp connection isn't already open,
333 it opens it. It then sends some data and waits for a reply. It
334 leaves the stream open on exit.
335 $p->ping_syn([$host, $ip, $start_time, $stop_time])
337 The "ping" method used with the syn protocol. Sends a TCP SYN
338 packet to host specified.
339 $p->ping_syn_fork([$host, $timeout, $family])
341 The "ping" method used with the forking syn protocol.
342 $p->ping_tcp([$host, $timeout, $family])
344 The "ping" method used with the tcp protocol.
345 $p->ping_udp([$host, $timeout, $family])
347 The "ping" method used with the udp protocol.
348 Perform a udp echo ping. Construct a message of at least the one-
350 byte sequence number and any additional data bytes. Send the
351 message out and wait for a message to come back. If we get a
352 message, make sure all of its parts match. If they do, we are
353 done. Otherwise go back and wait for the message until we run out
354 of time. Return the result of our efforts.
355 $p->ping_external([$host, $timeout, $family])
357 The "ping" method used with the external protocol. Uses
358 Net::Ping::External to do an external ping.
359 $p->tcp_connect([$ip, $timeout])
361 Initiates a TCP connection, for a tcp ping.
362 $p->tcp_echo([$ip, $timeout, $pingstring])
364 Performs a TCP echo. It writes the given string to the socket and
365 then reads it back. It returns 1 on success, 0 on failure.
366 $p->close();
368 Close the network connection for this ping object. The network
369 connection is also closed by "undef $p". The network connection is
370 automatically closed if the ping object goes out of scope (e.g. $p
371 is local to a subroutine and you leave the subroutine).
372 $p->port_number([$port_number])
374 When called with a port number, the port number used to ping is set
375 to $port_number rather than using the echo port. It also has the
376 effect of calling "$p->service_check(1)" causing a ping to return a
377 successful response only if that specific port is accessible. This
378 function returns the value of the port that "ping" will connect to.
379 $p->mselect
381 A select() wrapper that compensates for platform peculiarities.
382 $p->ntop
384 Platform abstraction over inet_ntop()
385 $p->checksum($msg)
387 Do a checksum on the message. Basically sum all of the short words
388 and fold the high order bits into the low order bits.
389 $p->icmp_result
391 Returns a list of addr, type, subcode.
392 pingecho($host [, $timeout]);
394 To provide backward compatibility with the previous version of
395 Net::Ping, a pingecho() subroutine is available with the same
396 functionality as before. pingecho() uses the tcp protocol. The
397 return values and parameters are the same as described for the
398 "ping" method. This subroutine is obsolete and may be removed in a
399 future version of Net::Ping.
400 wakeonlan($mac, [$host, [$port]])
402 Emit the popular wake-on-lan magic udp packet to wake up a local
403 device. See also Net::Wake, but this has the mac address as 1st
404 arg. $host should be the local gateway. Without it will broadcast.
405 Default host: '255.255.255.255' Default port: 9
407 perl -MNet::Ping=wakeonlan -e'wakeonlan "e0:69:95:35:68:d2"'
409
411 There will be less network overhead (and some efficiency in your
412 program) if you specify either the udp or the icmp protocol. The tcp
413 protocol will generate 2.5 times or more traffic for each ping than
414 either udp or icmp. If many hosts are pinged frequently, you may wish
415 to implement a small wait (e.g. 25ms or more) between each ping to
416 avoid flooding your network with packets.
417 The icmp and icmpv6 protocols requires that the program be run as root
419 or that it be setuid to root. The other protocols do not require
420 special privileges, but not all network devices implement tcp or udp
421 echo.
422 Local hosts should normally respond to pings within milliseconds.
424 However, on a very congested network it may take up to 3 seconds or
425 longer to receive an echo packet from the remote host. If the timeout
426 is set too low under these conditions, it will appear that the remote
427 host is not reachable (which is almost the truth).
428 Reachability doesn't necessarily mean that the remote host is actually
430 functioning beyond its ability to echo packets. tcp is slightly better
431 at indicating the health of a system than icmp because it uses more of
432 the networking stack to respond.
433 Because of a lack of anything better, this module uses its own routines
435 to pack and unpack ICMP packets. It would be better for a separate
436 module to be written which understands all of the different kinds of
437 ICMP packets.
438
440 The latest source tree is available via git:
441 git clone https://github.com/rurban/Net-Ping.git
443 cd Net-Ping
444 The tarball can be created as follows:
446 perl Makefile.PL ; make ; make dist
448 The latest Net::Ping releases are included in cperl and perl5.
450
452 For a list of known issues, visit:
453 <https://rt.cpan.org/NoAuth/Bugs.html?Dist=Net-Ping> and
455 <https://github.com/rurban/Net-Ping/issues>
456 To report a new bug, visit:
458 <https://github.com/rurban/Net-Ping/issues>
460
462 Current maintainers:
463 perl11 (for cperl, with IPv6 support and more)
464 p5p (for perl5)
465 Previous maintainers:
467 bbb@cpan.org (Rob Brown)
468 Steve Peters
469 External protocol:
471 colinm@cpan.org (Colin McMillen)
472 Stream protocol:
474 bronson@trestle.com (Scott Bronson)
475 Wake-on-lan:
477 1999-2003 Clinton Wong
478 Original pingecho():
480 karrer@bernina.ethz.ch (Andreas Karrer)
481 pmarquess@bfsec.bt.co.uk (Paul Marquess)
482 Original Net::Ping author:
484 mose@ns.ccsn.edu (Russell Mosemann)
485
487 Copyright (c) 2017-2020, Reini Urban. All rights reserved.
488 Copyright (c) 2016, cPanel Inc. All rights reserved.
490 Copyright (c) 2012, Steve Peters. All rights reserved.
492 Copyright (c) 2002-2003, Rob Brown. All rights reserved.
494 Copyright (c) 2001, Colin McMillen. All rights reserved.
496 This program is free software; you may redistribute it and/or modify it
498 under the same terms as Perl itself.
499perl v5.38.0 2023-07-21 Net::Ping(3)