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PING(8) System Manager's Manual: iputils PING(8)
NAME
ping, ping6 - send ICMP ECHO_REQUEST to network hosts
SYNOPSIS
ping [ -LRUbdfnqrvVaAB] [ -c count] [ -i interval] [ -l preload] [
-p pattern] [ -s packetsize] [ -t ttl] [ -w deadline] [ -F flowla-
bel] [ -I interface] [ -M hint] [ -P policy] [ -Q tos] [ -S snd-
buf] [ -T timestamp option] [ -W timeout] [ hop ...] destination
DESCRIPTION
ping uses the ICMP protocol's mandatory ECHO_REQUEST datagram to elicit
an ICMP ECHO_RESPONSE from a host or gateway. ECHO_REQUEST datagrams
(``pings'') have an IP and ICMP header, followed by a struct timeval
and then an arbitrary number of ``pad'' bytes used to fill out the
packet.
OPTIONS
-a Audible ping.
-A Adaptive ping. Interpacket interval adapts to round-trip time,
so that effectively not more than one (or more, if preload is
set) unanswered probes present in the network. Minimal interval
is 200msec for not super-user. On networks with low rtt this
mode is essentially equivalent to flood mode.
-b Allow pinging a broadcast address.
-B Do not allow ping to change source address of probes. The
address is bound to one selected when ping starts.
-c count
Stop after sending count ECHO_REQUEST packets. With deadline
option, ping waits for count ECHO_REPLY packets, until the time-
out expires.
-d Set the SO_DEBUG option on the socket being used. Essentially,
this socket option is not used by Linux kernel.
-F flow label
Allocate and set 20 bit flow label on echo request packets.
(Only ping6). If value is zero, kernel allocates random flow
label.
-f Flood ping. For every ECHO_REQUEST sent a period ``.'' is
printed, while for ever ECHO_REPLY received a backspace is
printed. This provides a rapid display of how many packets are
being dropped. If interval is not given, it sets interval to
zero and outputs packets as fast as they come back or one hun-
dred times per second, whichever is more. Only the super-user
may use this option with zero interval.
-i interval
Wait interval seconds between sending each packet. The default
is to wait for one second between each packet normally, or not
to wait in flood mode. Only super-user may set interval to val-
ues less 0.2 seconds.
-I interface address
Set source address to specified interface address. Argument may
be numeric IP address or name of device. When pinging IPv6 link-
local address this option is required.
-l preload
If preload is specified, ping sends that many packets not wait-
ing for reply. Only the super-user may select preload more than
3.
-L Suppress loopback of multicast packets. This flag only applies
if the ping destination is a multicast address.
-n Numeric output only. No attempt will be made to lookup symbolic
names for host addresses.
-P policy
Override system-wide IPsec policy. Argument is a string of for-
mat described in ipsec_set_policy(3). Couple of examples: "out
bypass" requests to bypass system-wide defaults, "out ipsec
esp/transport//require" demands to send ping packets using ESP
in transport mode.
-p pattern
You may specify up to 16 ``pad'' bytes to fill out the packet
you send. This is useful for diagnosing data-dependent problems
in a network. For example, -p ff will cause the sent packet to
be filled with all ones.
-Q tos Set Quality of Service -related bits in ICMP datagrams. tos can
be either decimal or hex number. Traditionally (RFC1349), these
have been interpreted as: 0 for reserved (currently being rede-
fined as congestion control), 1-4 for Type of Service and 5-7
for Precedence. Possible settings for Type of Service are: min-
imal cost: 0x02, reliability: 0x04, throughput: 0x08, low delay:
0x10. Multiple TOS bits should not be set simultaneously. Pos-
sible settings for special Precedence range from priority (0x20)
to net control (0xe0). You must be root (CAP_NET_ADMIN capabil-
ity) to use Critical or higher precedence value. You cannot set
bit 0x01 (reserved) unless ECN has been enabled in the kernel.
In RFC2474, these fields has been redefined as 8-bit Differenti-
ated Services (DS), consisting of: bits 0-1 of separate data
(ECN will be used, here), and bits 2-7 of Differentiated Ser-
vices Codepoint (DSCP).
-q Quiet output. Nothing is displayed except the summary lines at
startup time and when finished.
-R Record route. (IPv4 only) Includes the RECORD_ROUTE option in
the ECHO_REQUEST packet and displays the route buffer on
returned packets. Note that the IP header is only large enough
for nine such routes. Many hosts ignore or discard this option.
-r Bypass the normal routing tables and send directly to a host on
an attached interface. 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 no route
through it provided the option -I is also used.
-s packetsize
Specifies the number of data bytes to be sent. The default is
56, which translates into 64 ICMP data bytes when combined with
the 8 bytes of ICMP header data.
-S sndbuf
Set socket sndbuf. If not specified, it is selected to buffer
not more than one packet.
-t ttl Set the IP Time to Live.
-T timestamp option
Set special IP timestamp options. timestamp option may be
either tsonly (only timestamps), tsandaddr (timestamps and
addresses) or tsprespec host1 [host2 [host3 [host4]]] (timestamp
prespecified hops).
-M hint
Select Path MTU Discovery strategy. hint may be either do (pro-
hibit fragmentation, even local one), want (do PMTU discovery,
fragment locally when packet size is large), or dont (do not set
DF flag).
-U Print full user-to-user latency (the old behaviour). Normally
ping prints network round trip time, which can be different f.e.
due to DNS failures.
-v Verbose output.
-V Show version and exit.
-w deadline
Specify a timeout, in seconds, before ping exits regardless of
how many packets have been sent or received. In this case ping
does not stop after count packet are sent, it waits either for
deadline expire or until count probes are answered or for some
error notification from network.
-W timeout
Time to wait for a response, in seconds. The option affects only
timeout in absense of any responses, otherwise ping waits for
two RTTs.
When using ping for fault isolation, it should first be run on the
local host, to verify that the local network interface is up and run-
ning. Then, hosts and gateways further and further away should be
``pinged''. Round-trip times and packet loss statistics are computed.
If duplicate packets are received, they are not included in the packet
loss calculation, although the round trip time of these packets is used
in calculating the minimum/average/maximum round-trip time numbers.
When the specified number of packets have been sent (and received) or
if the program is terminated with a SIGINT, a brief summary is dis-
played. Shorter current statistics can be obtained without termination
of process with signal SIGQUIT.
If ping does not receive any reply packets at all it will exit with
code 1. If a packet count
iputils-021109 09 2002 PING(8)
