ping(1M) ping(1M)
NAME [Toc] [Back]
ping - send ICMP Echo Request packets to network host
SYNOPSIS [Toc] [Back]
ping [-oprv] [-f address-family] [-i address] [-I interval] [-t ttl]
host [-n count [-m timeout]]
ping [-oprv] [-f address-family] [-i address] [-I interval] [-t ttl]
host packet-size [ [-n] count [-m timeout]]
DESCRIPTION [Toc] [Back]
The ping command sends ICMP Echo Request (ECHO_REQUEST) packets to the
host once per second. Each packet that is echoed back via an ICMP
Echo Response packet is written to the standard output, including
round-trip time.
ICMP Echo Request datagrams ("pings") have an IP and ICMP header,
followed by a struct timeval (see gettimeofday(2)) and an arbitrary
number of "pad" bytes used to fill out the packet. The default
datagram length is 64 bytes, but this can be changed by using the
packet-size option.
Options [Toc] [Back]
The following options and parameters are recognized by ping:
-i address If host is a multicast address, send multicast
datagrams from the interface with the local IP
address specified by address in ``dot'' notation (see
inet(3N)). If the -i option is not specified,
multicast datagrams are sent from the default
interface, which is determined by the route
configuration.
-o Insert an IP Record Route option in outgoing packets,
summarizing routes taken when the command terminates.
It may not be possible to get the round-trip path if
some hosts on the route taken do not implement the IP
Record Route option. A maximum of 9 Internet
addresses can be recorded due to the maximum length
of the IP option area.
-p The new Path MTU information is displayed when a ICMP
Datagram Too Big message is received from a gateway.
The -p option must be used in conjunction with a
large packetsize and with the -v option.
-r Bypass the normal routing tables and send directly to
a host on an attached network. If the host is not on
a directly-connected network, an error is returned.
This option can be used to ping the local system
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through an interface that has no route through it,
such as, after the interface was dropped by gated
(see gated(1M)).
-t ttl If host is a multicast address, set the time-to-live
field in the multicast datagram to ttl. This
controls the scope of the multicast datagrams by
specifying the maximum number of external systems
through which the datagram can be forwarded.
If ttl is zero, the datagram is restricted to the
local system. If ttl is one, the datagram is
restricted to systems that have an interface on the
network directly connected to the interface specified
by the -i option. If ttl is two, the datagram can be
forwarded through one multicast router at the most;
and so forth. Range: zero to 255. The default value
is 1.
-I interval This option specifies the interval in seconds,
between each packet to be transmitted. The default
interval is 1 second.
-v Verbose output. Show ICMP packets other than Echo
Responses that are received.
-f address-family
The address-family determines whether the host is an
IPv4 or IPv6 host. The address families currently
supported are inet for IPv4 addresses and inet6 for
IPv6 addresses.
host Destination to which the ICMP Echo Requests are sent.
host can be a hostname or an IPv4 or IPv6 Internet
address. All symbolic names specified for host are
looked up by using gethostbyname() (see
gethostent(3N)) for IPv4, and getaddrinfo() (see
getaddrinfo(3N)) for IPv6. If host is an Internet
address, it must be in "dot" notation (see inet(3N))
for IPv4, and in "colon" notation (see inet6(3N)) for
IPv6.
If the address-family is specified, and host is an
Internet address, the address family of the Internet
address must be the same as that specified in the
address-family option. If the address-family is not
specified, and host is a symbolic name, an attempt
will be made to resolve host into an IPv4 address
first. If that fails, a second attempt will be made
to resolve host into an IPv6 address.
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ping(1M) ping(1M)
The ping command does not accept IPv4-mapped IPv6
addresses. To ping an IPv4 node, an IPv4 address
should be used. IPv4-mapped IPv6 addresses are used
to address IPv4-only nodes from an IPv6 node in a
socket program only. IPv4-mapped IPv6 addresses are
always converted to an IPv4 address before they are
used in packets sent over the network.
If a system does not respond as expected, the route
might be configured incorrectly on the local or
remote system or on an intermediate gateway, or there
might be some other network failure. Normally, host
is the address assigned to a local or remote network
interface.
(inet only) If host is a broadcast address, all
systems that receive the broadcast should respond.
Normally, these are only systems that have a network
interface on the same network as the local interface
sending the ICMP Echo Request.
If host is a multicast address, only systems that
have joined the multicast group should respond.
These may be distant systems if the -t option is
specified, and there is a multicast router on the
network directly connected to the interface specified
by the -i option.
packet-size The size of the transmitted packet, in bytes. By
default (when packet-size is not specified), the size
of transmitted packets is 64 bytes. The minimum
value allowed for packet-size is 8 bytes, and the
maximum value is 4095 bytes. If packet-size is
smaller than 16 bytes, there is not enough room for
timing information. In that case, the round-trip
times are not displayed.
-n count The number of packets ping will transmit before
terminating. The -n is not needed if also specifying
packet-size. Range: zero to 2147483647. The default
is zero, in which case ping sends packets until
interrupted.
-m timeout Override the default timeout value (10 seconds) which
ping uses to timeout (in seconds) when a host or
network is unreachable. This option is valid only
with the -n option or when count is specified. The
-m option should not be used with count equal to 0.
The -m option is not effective for reachable hosts or
networks.
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ping(1M) ping(1M)
Using ping for Fault Isolation [Toc] [Back]
When using ping for fault isolation, first specify a local address for
host to verify that the local network interface is working correctly.
Then specify host and gateway addresses further and further away to
determine the point of failure. ping sends one datagram per second,
and it normally writes one line of output for every ICMP Echo Response
that is received. No output is produced if there are no responses.
If an optional count is given, only the specified number of requests
is sent. Round-trip times and packet loss statistics are computed.
When all responses have been received or the command times out (if the
count option is specified), or if the command is terminated with a
SIGINT, a brief summary is displayed.
This command is intended for use in testing, managing and measuring
network performance. It should be used primarily to isolate network
failures. Because of the load it could impose on the network, it is
considered discourteous to use ping unnecessarily during normal
operations or from automated scripts.
RETURN VALUE [Toc] [Back]
ping exits with one of the following values:
0 On success.
1 On failure such as unknown host, illegal packet size, etc.
2 On a unreachable host or network.
AUTHOR [Toc] [Back]
ping was developed in the Public Domain.
FILES [Toc] [Back]
/etc/hosts
SEE ALSO [Toc] [Back]
getaddrinfo(3N), gethostent(3N), inet(3N), inet6(3N).
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