ping Command

Purpose

Sends an echo request to a network host.

Syntax

ping [ -d] [ -D ] [  -n] [  -q] [ -r] [ -v] [  -R] [ -a addr_family ] [  -c Count ] [ -w timeout ] [  -f|  -i Wait ] [  -l Preload ] [  -p Pattern ] [  -s PacketSize ] [ -S hostname/IP addr ] [ -L ] [ -I a.b.c.d. ] [ -o interface ] [ -T ttl ] [-E Interface_name | Source_Hostname | Source_IP_address] Host [  PacketSize ] [  Count ]

Description

The /usr/sbin/ping command sends an Internet Control Message Protocol (ICMP) ECHO_REQUEST to obtain an ICMP ECHO_RESPONSE from a host or gateway. The ping command is useful for the following functions:

Determining the status of the network and various foreign hosts.
Tracking and isolating hardware and software problems.
Testing, measuring, and managing networks.

If the host is operational and on the network, it responds to the echo. Each echo request contains an Internet Protocol (IP) and ICMP header, followed by a ping PID and a timeval structure, and enough bytes to complete the packet. The default is to continuously send echo requests until an Interrupt is received (Ctrl-C).

The ping command sends one datagram per second and prints one line of output for every response received. The ping command calculates round-trip times and packet loss statistics, and displays a brief summary on completion. The ping command completes when the program times out or on receipt of a SIGINT signal. The Host parameter is either a valid hostname or Internet address.

By default, the ping command continues to send echo requests to the display until an Interrupt is received (Ctrl-C). The Interrupt key can be changed by using the stty command.

Because of the load that continuous echo requests can place on the system, repeated requests must be used primarily for problem isolation.

Flags

Table 1. Flags
Item	Description
-c `Count`	Specifies the number of echo requests, as indicated by the `Count` variable, to be sent (and received).
-w `timeout`	This option works only with the -c option. It causes ping to wait for a maximum of 'timeout' seconds for a reply (after sending the last packet).
-d	Starts socket-level debugging.
-D	This option causes a hex dump to standard output of ICMP ECHO_REPLY packets.
-E `Interface_name` \| `Source_Hostname` \| `Source_IP_address`	Sends or receives ping packets over specific interface for both IPv4 and IPv6 protocols. When you specify an interface name, a source hostname, or a source IP address that is not one of the machine's interface addresses, an error is returned and no ping packets are sent. If you specify an interface name with the -E flag, by default, the number of echo requests (-c `Count`) is set to a value of 5. Notes: The -E flag ensures to send or receive a ping packet over specific interface. The -E flag works only on destination media access control (MAC) address, and not on the saved routes. Therefore, the -E flag works in the IPv4 protocol only if the address resolution protocol (ARP) is resolved. The -E flag works in the IPv6 protocol only if the neighbor discovery protocol (NDP) resolves an IPv6 address into a MAC address. You cannot run the -R flag with the -E option because the -E flag does not work on saved routes.
-f	Specifies flood-ping option. The -f flag "floods" or outputs packets as fast as they come back or 100 times per second, whichever is more. For every ECHO_REQUEST sent, a. (period) is printed, while for every ECHO_REPLY received, a backspace is printed. This provides a rapid display of how many packets are being dropped. Only the root user can use this option. Note: Use this flag with caution. Flood pinging is only permitted by the root user. The -f flag is incompatible with the -i`Wait` flag.
-I `a.b.c.d`	Specifies that the interface specified by `a.b.c.d` is to be used for outgoing IPv4 multicasts. The -I flag is an uppercase i.
-o `interface`	Specifies that `interface` is to be used for outgoing IPv6 multicasts. The interface is specified in the form 'en0', 'tr0', and so on.
-i `Wait`	Waits the number of seconds specified by the `Wait` variable between the sending of each packet. The default is to wait for one second between each packet. This option is incompatible with the -f flag.
-L	Disables local loopback for multicast pings.
-l `Preload`	Sends the number of packets that are specified by the `Preload` variable as fast as possible before falling into normal mode of behavior (one per second). The -l flag is a lowercase l.
-n	Specifies numeric output only. No attempt is made to look up symbolic names for host addresses.
-p `Pattern`	Specifies up to 16 'pad' bytes to complete the packet you send. This is useful for diagnosing data-dependent problems in a network. For example, `-p ff` fills the packet with all 1's.
-q	Specifies quiet output. Nothing is displayed except the summary lines at startup time and when finished.
-r	Bypasses the routing tables and sends directly to a host on an attached network. If the `Host` is not on a directly connected network, the ping command generates an error message. This option can be used to ping a local host through an interface that no longer has a route through it.
-R	Specifies record route option. The -R flag includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note: The IP header is only large enough for nine such routes. Also, many hosts and gateways ignore this option.
-a `addr_family`	Maps the destination address of the ICMP packets to IPv6 format if addr_family is equal to "inet6".
-s `PacketSize`	Specifies the number of data bytes to be sent. The default is 56, which converts into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data.
-S `hostname/IP addr`	Uses the IP address as the source address in outgoing ping packets. On hosts with more than one IP address, the -S flag can be used to send or receive ping packets by using a specific source IP address. If the IP address is not one of the machine's interface addresses, an error is returned and nothing is sent. Note: You can use the -S flag to send or receive the ping packet by using a specific source IP address, but the -S flag does not guarantee to send or receive ping packet over specific interface. Instead, use -E flag that ensures to send or receive ping packet over specific interface.
-T `ttl`	Specifies that the time to live for a multicast packet is `ttl` seconds.
-v	Requests verbose output, which lists ICMP packets that are received in addition to echo responses.

Parameters

Table 2. Parameters
Item	Description
`PacketSize`	Specifies the number of data bytes to be sent. The default is 56, which converts into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data. This parameter is included for compatibility with previous versions of the ping command.
`Count`	Specifies the number of echo requests to be sent (and received). This parameter is included for compatibility with previous versions of the ping command.

Security

Attention RBAC users: Attention RBAC users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations that are associated with this command, see the lssecattr command or the getcmdattr subcommand.

Examples

To check the network connection to the host canopus and specify the number of echo requests to send, enter:

ping  -c 5 canopus

ping canopus  56  5

Information similar to the following is displayed:

PING canopus.austin.century.com: (128.116.1.5): 56 data bytes
64 bytes from 128.116.1.5: icmp_seq=0 ttl=255 time=2 ms
64 bytes from 128.116.1.5: icmp_seq=1 ttl=255 time=2 ms
64 bytes from 128.116.1.5: icmp_seq=2 ttl=255 time=3 ms
64 bytes from 128.116.1.5: icmp_seq=3 ttl=255 time=2 ms
64 bytes from 128.116.1.5: icmp_seq=4 ttl=255 time=2 ms

----canopus.austin.century.com PING Statistics----
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 2/2/3 ms

To get information about host lear and start socket-level debugging, enter:

ping  -d  lear

Information similar to the following is displayed:

PING lear.austin.century.com: (128.114.4.18) 56 data bytes
64 bytes from 128.114.4.18: icmp_seq=0 ttl=255 time=6 ms
64 bytes from 128.114.4.18: icmp_seq=1 ttl=255 time=17 ms
64 bytes from 128.114.4.18: icmp_seq=2 ttl=255 time=6 ms
64 bytes from 128.114.4.18: icmp_seq=3 ttl=255 time=6 ms
64 bytes from 128.114.4.18: icmp_seq=4 ttl=255 time=6 ms
^C
----lear.austin.century.com PING Statistics ----
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 6/8/17 ms