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ping(1M) ping(1M) NAME
ping - send ICMP Echo Request packets to network host SYNOPSIS
address-family] address] interval] ttl] host count timeout]] address-family] address] interval] ttl] host packet-size count timeout]] DESCRIPTION
The 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 (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 The following options and parameters are recognized by 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 option is not specified, multicast datagrams are sent from the default inter- face, which is determined by the route configuration. If host is not a multicast address, the option is ignored. 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. The new Path MTU information is displayed when a ICMP message is received from a gateway. The option must be used in conjunction with a large packetsize and with the option. 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 through an interface that has no route through it, such as, after the inter- face was dropped by (see gated(1M)). 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 for- warded. 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 option. If ttl is two, the datagram can be forwarded through one multicast router at the most; and so forth. zero to 255. The default value is 1. This option specifies the interval in seconds, between each packet to be transmitted. The default interval is 1 second. Verbose output. Show ICMP packets other than Echo Responses that are received. The address-family determines whether the host is an IPv4 or IPv6 host. The address families currently supported are for IPv4 addresses and 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 (see gethostent(3N)) for IPv4, and (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. 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 option is specified, and there is a multicast router on the network directly connected to the interface specified by the 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 65500 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. The number of packets will transmit before terminating. The is not needed if also specifying packet-size. Range: zero to 2147483647. The default is zero, in which case sends packets until interrupted. Override the default timeout value (10 seconds) which uses to timeout (in seconds) when a host or network is unreachable. This option is valid only with the option or when count is specified. The option should not be used with count equal to 0. The option is not effective for reachable hosts or networks. Using ping for Fault Isolation When using 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. 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 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 unnecessarily during normal operations or from automated scripts. RETURN VALUE
exits with one of the following values: On success. On failure such as unknown host, illegal packet size, etc. On a unreachable host or network. AUTHOR
was developed in the Public Domain. FILES
SEE ALSO
getaddrinfo(3N), gethostent(3N), inet(3N), inet6(3N). ping(1M)
