The utility ping utilizes the ICMP (ICMP6 in IPv6) protocol's ECHO_REQUEST datagram to elicit an ICMP (ICMP6) ECHO_RESPONSE from the specified host or network gateway. If host responds, ping will print:

host is alive

on the standard output and exit. Otherwise, after timeout seconds, it will write:

no answer from host

The default value of timeout is 20 seconds.

When you specify the s flag, sends one datagram per second (adjust with -I) and prints one line of output for every ECHO_RESPONSE that it receives. ping produces no output if there is no response. In this second form, ping computes round trip times and packet loss statistics; it displays a summary of this information upon termination or timeout. The default data_size is 56 bytes, or you can specify a size with the data_size command-line argument. If you specify the optional npackets, ping sends ping requests until it either sends npackets requests or receives npackets replies.

When using ping for fault isolation, first ping the local host to verify that the local network interface is running.

The following options are supported:

-A addr_family

Specify the address family of the target host. addr_family can be either inet or inet6. Address family determines which protocol to use. For an argument of inet, IPv4 is used. For inet6, IPv6 is used.

By default, if the name of a host is provided, not the literal IP address, and a valid IPv6 address exists in the name service database, ping will use this address. Otherwise, if the name service database contains an IPv4 address, it will try the IPv4 address.

Specify the address family inet or inet6 to override the default behavior. If the argument specified is inet, ping will use the IPv4 address associated with the host name. If none exists, ping will state that the host is unknown and exit. It does not try to determine if an IPv6 address exists in the name service database.

If the specified argument is inet6, ping uses the IPv6 address that is associated with the host name. If none exists, ping states that the host is unknown and exits.

-F flow_label

Specify the flow label of probe packets. The value must be an integer in the range from 0 to 1048575. This option is valid only on IPv6.

-I interval

Turn on the statistics mode and specify the interval between successive transmissions. The default is one second. See the discussion of the -s option.

-L

Turn off loopback of multicast packets. Normally, members are in the host group on the outgoing interface, a copy of the multicast packets will be delivered to the local machine.

-P tos

Set the type of service (tos) in probe packets to the specified value. The default is zero. The value must be an integer in the range from 0 to 255. Gateways also in the path can route the probe packet differently, depending upon the value of tos that is set in the probe packet. This option is valid only on IPv4.

-R

Record route. Sets the IPv4 record route option, which stores the route of the packet inside the IPv4 header. The contents of the record route are only printed if the -v and -s options are given. They are only set on return packets if the target host preserves the record route option across echos, or the -l option is given. This option is valid only on IPv4.

-U

Send UDP packets instead of ICMP (ICMP6) packets. ping sends UDP packets to consecutive ports expecting to receive back ICMP (ICMP6) PORT_UNREACHABLE from the target host.

-a

ping all addresses, both IPv4 and IPv6, of the multihomed destination. The output appears as if ping has been run once for each IP address of the destination. If this option is used together with -A, ping probes only the addresses that are of the specified address family. When used with the -s option and npackets is not specified, ping continuously probes the destination addresses in a round robin fashion. If npackets is specified, ping sends npackets number of probes to each IP address of the destination and then exits.

-c traffic_class

Specify the traffic class of probe packets. The value must be an integer in the range from 0 to 255. Gateways along the path can route the probe packet differently, depending upon the value of traffic_class set in the probe packet. This option is valid only on IPv6.

-d

Set the SO_DEBUG socket option.

-g gateway

Specify a loose source route gateway so that the probe packet goes through the specified host along the path to the target host. The maximum number of gateways is 8 for IPv4 and 127 for IPv6. Note that some factors such as the link MTU can further limit the number of gateways for IPv6.

-i interface_address

Specify the outgoing interface address to use for multicast packets for IPv4 and both multicast and unicast packets for IPv6. The default interface address for multicast packets is determined from the (unicast) routing tables. interface_address can be a literal IP address, for example, 10.123.100.99, or an interface name, for example, le0, or an interface index, for example 2.

-l

Use to send the probe packet to the given host and back again using loose source routing. Usually specified with the -R option. If any gateways are specified using -g, they are visited twice, both to and from the destination. This option is ignored if the -U option is used.

-n

Show network addresses as numbers. ping normally does a reverse name lookup on the IP addresses it extracts from the packets received. The -n option blocks the reverse lookup, so ping prints IP addresses instead of host names.

-p port

Set the base UDP port number used in probes. This option is used with the -U option. The default base port number is 33434. The ping utility starts setting the destination port number of UDP packets to this base and increments it by one at each probe.

-r

Bypass the normal routing tables and send directly to a host on an attached network. If the host is not on a directly attached network, an error is returned. This option can be used to ping a local host through an interface that has been dropped by the router daemon. See in.routed(1M).

-s

Send one datagram per second and collect statistics.

-t  ttl

Specify the IPv4 time to live, or IPv6 hop limit, for unicast and multicast packets. The default time to live (hop limit) for unicast packets can be set with ndd(1M) using the icmp_ipv4_ttl variable for IPv4 and the icmp_ipv6_ttl variable for IPv6. The default time to live (hop limit) for multicast is one hop.

-v

Verbose output. List any ICMP (ICMP6) packets, other than replies from the target host.

host

The network host

The following exit values are returned:

0

Successful operation; the machine is alive.

non-zero

An error has occurred. Either a malformed argument has been specified, or the machine was not alive.

See attributes(5) for descriptions of the following attributes:

ifconfig(1M), in.routed(1M), ndd(1M), netstat(1M), rpcinfo(1M), traceroute(1M), attributes(5), icmp(7P), icmp6(7P)