<refentry xmlns:db="http://docbook.org/ns/docbook" version="5.0"
xml:id="man.ping">
<refentryinfo>
<title>ping</title>
<productname>iputils</productname>
</refentryinfo>
<refmeta>
<refentrytitle>
<application>ping</application>
</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class='manual'>iputils</refmiscinfo>
</refmeta>
<refnamediv>
<refname>ping</refname>
<refpurpose>send ICMP ECHO_REQUEST to network
hosts</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis sepchar=" ">
<command>ping</command>
<arg choice="opt" rep="norepeat">
<option>-aAbBdDfhLnOqrRUvV46</option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-c
<replaceable>count</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-F
<replaceable>flowlabel</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-i
<replaceable>interval</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-I
<replaceable>interface</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-l
<replaceable>preload</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-m
<replaceable>mark</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-M
<replaceable>pmtudisc_option</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-N
<replaceable>nodeinfo_option</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-w
<replaceable>deadline</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-W
<replaceable>timeout</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-p
<replaceable>pattern</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-Q
<replaceable>tos</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-s
<replaceable>packetsize</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-S
<replaceable>sndbuf</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-t
<replaceable>ttl</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">
<option>-T
<replaceable>timestamp option</replaceable></option>
</arg>
<arg choice="opt" rep="norepeat">hop...</arg>
<arg choice="req" rep="norepeat">destination</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsection>
<info>
<title>DESCRIPTION</title>
</info>
<para>
<command>ping</command> 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.</para>
<para>
<command>ping</command> works with both IPv4 and IPv6. Using
only one of them explicitly can be enforced by specifying
<option>-4</option> or
<option>-6</option>.</para>
<para>
<command>ping</command> can also send IPv6 Node Information
Queries (RFC4620). Intermediate
<emphasis remap="I">hop</emphasis>s may not be allowed, because
IPv6 source routing was deprecated (RFC5095).</para>
</refsection>
<refsection>
<info>
<title>OPTIONS</title>
</info>
<variablelist remap="TP">
<varlistentry>
<term>
<option>-4</option>
</term>
<listitem>
<para>Use IPv4 only.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-6</option>
</term>
<listitem>
<para>Use IPv6 only.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-a</option>
</term>
<listitem>
<para>Audible ping.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-A</option>
</term>
<listitem>
<para>Adaptive ping. Interpacket interval adapts to
round-trip time, so that effectively not more than one
(or more, if preload is set) unanswered probe is present
in the network. Minimal interval is 200msec unless
super-user. On networks with low RTT this mode is
essentially equivalent to flood mode.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-b</option>
</term>
<listitem>
<para>Allow pinging a broadcast address.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-B</option>
</term>
<listitem>
<para>Do not allow
<command>ping</command> to change source address of
probes. The address is bound to one selected when
<command>ping</command> starts.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-c</option>
<emphasis remap="I">count</emphasis>
</term>
<listitem>
<para>Stop after sending
<emphasis remap="I">count</emphasis> ECHO_REQUEST packets.
With
<emphasis remap="I">deadline</emphasis> option,
<command>ping</command> waits for
<emphasis remap="I">count</emphasis> ECHO_REPLY packets,
until the timeout expires.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-d</option>
</term>
<listitem>
<para>Set the SO_DEBUG option on the socket being used.
Essentially, this socket option is not used by Linux
kernel.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-D</option>
</term>
<listitem>
<para>Print timestamp (unix time + microseconds as in
gettimeofday) before each line.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-f</option>
</term>
<listitem>
<para>Flood ping. 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. If interval is not
given, it sets interval to zero and outputs packets as
fast as they come back or one hundred times per second,
whichever is more. Only the super-user may use this
option with zero interval.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-F</option>
<emphasis remap="I">flow label</emphasis>
</term>
<listitem>
<para>IPv6 only. Allocate and set 20 bit flow label (in
hex) on echo request packets. If value is zero, kernel
allocates random flow label.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-h</option>
</term>
<listitem>
<para>Show help.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-i</option>
<emphasis remap="I">interval</emphasis>
</term>
<listitem>
<para>Wait
<emphasis remap="I">interval</emphasis> seconds between
sending each packet. Real number allowed with dot as
a decimal separator (regardless locale setup).
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 values
less than 0.2 seconds.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-I</option>
<emphasis remap="I">interface</emphasis>
</term>
<listitem>
<para>
<emphasis remap="I">interface</emphasis> is either an
address, an interface name or a VRF name. If
<emphasis remap="I">interface</emphasis> is an address, it
sets source address to specified interface address. If
<emphasis remap="I">interface</emphasis> is an interface
name, it sets source interface to specified interface.
If <emphasis remap="I">interface</emphasis> is a VRF
name, each packet is routed using the corresponding
routing table; in this case, the <option>-I</option> option
can be repeated to specify a source address.
NOTE: For IPv6, when doing ping to a link-local scope
address, link specification (by the '%'-notation in
<emphasis remap="I">destination</emphasis>, or by this
option) can be used but it is no longer required.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-l</option>
<emphasis remap="I">preload</emphasis>
</term>
<listitem>
<para>If
<emphasis remap="I">preload</emphasis> is specified,
<command>ping</command> sends that many packets not
waiting for reply. Only the super-user may select preload
more than 3.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-L</option>
</term>
<listitem>
<para>Suppress loopback of multicast packets. This flag
only applies if the ping destination is a multicast
address.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-m</option>
<emphasis remap="I">mark</emphasis>
</term>
<listitem>
<para>use
<emphasis remap="I">mark</emphasis> to tag the packets
going out. This is useful for variety of reasons within
the kernel such as using policy routing to select
specific outbound processing.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-M</option>
<emphasis remap="I">pmtudisc_opt</emphasis>
</term>
<listitem>
<para>Select Path MTU Discovery strategy.
<emphasis remap="I">pmtudisc_option</emphasis> may be
either
<emphasis remap="I">do</emphasis> (prohibit fragmentation,
even local one),
<emphasis remap="I">want</emphasis> (do PMTU discovery,
fragment locally when packet size is large), or
<emphasis remap="I">dont</emphasis> (do not set DF
flag).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-N</option>
<emphasis remap="I">nodeinfo_option</emphasis>
</term>
<listitem>
<para>IPv6 only. Send ICMPv6 Node Information Queries
(RFC4620), instead of Echo Request. CAP_NET_RAW
capability is required.</para>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">help</emphasis>
</term>
<listitem>
<para>Show help for NI support.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">name</emphasis>
</term>
<listitem>
<para>Queries for Node Names.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv6</emphasis>
</term>
<listitem>
<para>Queries for IPv6 Addresses. There are several
IPv6 specific flags.</para>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv6-global</emphasis>
</term>
<listitem>
<para>Request IPv6 global-scope
addresses.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv6-sitelocal</emphasis>
</term>
<listitem>
<para>Request IPv6 site-local
addresses.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv6-linklocal</emphasis>
</term>
<listitem>
<para>Request IPv6 link-local
addresses.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv6-all</emphasis>
</term>
<listitem>
<para>Request IPv6 addresses on other
interfaces.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv4</emphasis>
</term>
<listitem>
<para>Queries for IPv4 Addresses. There is one IPv4
specific flag.</para>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">ipv4-all</emphasis>
</term>
<listitem>
<para>Request IPv4 addresses on other
interfaces.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">subject-ipv6=</emphasis><emphasis remap="I">ipv6addr</emphasis>
</term>
<listitem>
<para>IPv6 subject address.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">subject-ipv4=</emphasis><emphasis remap="I">ipv4addr</emphasis>
</term>
<listitem>
<para>IPv4 subject address.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">subject-name=</emphasis><emphasis remap="I">nodename</emphasis>
</term>
<listitem>
<para>Subject name. If it contains more than one
dot, fully-qualified domain name is assumed.</para>
</listitem>
</varlistentry>
</variablelist>
<variablelist remap="TP">
<varlistentry>
<term>
<emphasis remap="B">subject-fqdn=</emphasis><emphasis remap="I">nodename</emphasis>
</term>
<listitem>
<para>Subject name. Fully-qualified domain name is
always assumed.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-n</option>
</term>
<listitem>
<para>Numeric output only. No attempt will be made to
lookup symbolic names for host addresses.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-O</option>
</term>
<listitem>
<para>Report outstanding ICMP ECHO reply before sending
next packet. This is useful together with the timestamp
<option>-D</option> to log output to a diagnostic file and
search for missing answers.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-p</option>
<emphasis remap="I">pattern</emphasis>
</term>
<listitem>
<para>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,
<option>-p ff</option> will cause the sent packet to be
filled with all ones.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-q</option>
</term>
<listitem>
<para>Quiet output. Nothing is displayed except the
summary lines at startup time and when finished.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-Q</option>
<emphasis remap="I">tos</emphasis>
</term>
<listitem>
<para>Set Quality of Service -related bits in ICMP
datagrams.
<emphasis remap="I">tos</emphasis> can be decimal
(<command>ping</command> only) or hex number.</para>
<para>In RFC2474, these fields are interpreted as 8-bit
Differentiated Services (DS), consisting of: bits 0-1 (2
lowest bits) of separate data, and bits 2-7 (highest 6
bits) of Differentiated Services Codepoint (DSCP). In
RFC2481 and RFC3168, bits 0-1 are used for ECN.</para>
<para>Historically (RFC1349, obsoleted by RFC2474), these
were interpreted as: bit 0 (lowest bit) for reserved
(currently being redefined as congestion control), 1-4
for Type of Service and bits 5-7 (highest bits) for
Precedence.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-r</option>
</term>
<listitem>
<para>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
<option>-I</option> is also used.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-R</option>
</term>
<listitem>
<para>
<command>ping</command> only. Record route. 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.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-s</option>
<emphasis remap="I">packetsize</emphasis>
</term>
<listitem>
<para>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.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-S</option>
<emphasis remap="I">sndbuf</emphasis>
</term>
<listitem>
<para>Set socket sndbuf. If not specified, it is selected
to buffer not more than one packet.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-t</option>
<emphasis remap="I">ttl</emphasis>
</term>
<listitem>
<para>
<command>ping</command> only. Set the IP Time to
Live.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-T</option>
<emphasis remap="I">timestamp option</emphasis>
</term>
<listitem>
<para>Set special IP timestamp options.
<emphasis remap="I">timestamp option</emphasis> may be
either
<emphasis remap="I">tsonly</emphasis> (only timestamps),
<emphasis remap="I">tsandaddr</emphasis> (timestamps and
addresses) or
<emphasis remap="I">tsprespec host1 [host2 [host3
[host4]]]</emphasis> (timestamp prespecified hops).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-U</option>
</term>
<listitem>
<para>Print full user-to-user latency (the old
behaviour). Normally
<command>ping</command> prints network round trip time,
which can be different f.e. due to DNS failures.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-v</option>
</term>
<listitem>
<para>Verbose output. Do not suppress DUP replies when pinging
multicast address.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-V</option>
</term>
<listitem>
<para>Show version and exit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-w</option>
<emphasis remap="I">deadline</emphasis>
</term>
<listitem>
<para>Specify a timeout, in seconds, before
<command>ping</command> exits regardless of how many
packets have been sent or received. In this case
<command>ping</command> does not stop after
<emphasis remap="I">count</emphasis> packet are sent, it
waits either for
<emphasis remap="I">deadline</emphasis> expire or until
<emphasis remap="I">count</emphasis> probes are answered
or for some error notification from network.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-W</option>
<emphasis remap="I">timeout</emphasis>
</term>
<listitem>
<para>Time to wait for a response, in seconds. The option
affects only timeout in absence of any responses,
otherwise
<command>ping</command> waits for two RTTs.
Real number allowed with dot as a decimal separator
(regardless locale setup).
0 means infinite timeout.</para>
</listitem>
</varlistentry>
</variablelist>
<para>When using
<command>ping</command> for fault isolation, it should first be
run on the local host, to verify that the local network
interface is up and running. 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/mdev round-trip time
numbers.</para>
<para>Population standard deviation (mdev), essentially an
average of how far each ping RTT is from the mean RTT. The
higher mdev is, the more variable the RTT is (over time).
With a high RTT
variability, you will have speed issues with bulk transfers
(they will take longer than is strictly speaking necessary, as
the variability will eventually cause the sender to wait for
ACKs) and you will have middling to poor VoIP quality.</para>
<para>When the specified number of packets have been sent (and
received) or if the program is terminated with a SIGINT, a
brief summary is displayed. Shorter current statistics can be
obtained without termination of process with signal
SIGQUIT.</para>
<para>If
<command>ping</command> does not receive any reply packets at
all it will exit with code 1. If a packet
<emphasis remap="I">count</emphasis> and
<emphasis remap="I">deadline</emphasis> are both specified, and
fewer than
<emphasis remap="I">count</emphasis> packets are received by the
time the
<emphasis remap="I">deadline</emphasis> has arrived, it will
also exit with code 1. On other error it exits with code 2.
Otherwise it exits with code 0. This makes it possible to use
the exit code to see if a host is alive or not.</para>
<para>This program is intended for use in network testing,
measurement and management. Because of the load it can impose
on the network, it is unwise to use
<command>ping</command> during normal operations or from
automated scripts.</para>
</refsection>
<refsection xml:id="icmp_packet_details">
<info>
<title>ICMP PACKET DETAILS</title>
</info>
<para>An IP header without options is 20 bytes. An ICMP
ECHO_REQUEST packet contains an additional 8 bytes worth of
ICMP header followed by an arbitrary amount of data. When a
<emphasis remap="I">packetsize</emphasis> is given, this
indicates the size of this extra piece of data (the default is
56). Thus the amount of data received inside of an IP packet of
type ICMP ECHO_REPLY will always be 8 bytes more than the
requested data space (the ICMP header).</para>
<para>If the data space is at least of size of struct timeval
<command>ping</command> uses the beginning bytes of this space
to include a timestamp which it uses in the computation of
round trip times. If the data space is shorter, no round trip
times are given.</para>
</refsection>
<refsection xml:id="duplicate_and_damaged_packets">
<info>
<title>DUPLICATE AND DAMAGED PACKETS</title>
</info>
<para>
<command>ping</command> will report duplicate and damaged
packets. Duplicate packets should never occur, and seem to be
caused by inappropriate link-level retransmissions. Duplicates
may occur in many situations and are rarely (if ever) a good
sign, although the presence of low levels of duplicates may not
always be cause for alarm.</para>
<para>Damaged packets are obviously serious cause for alarm and
often indicate broken hardware somewhere in the
<command>ping</command> packet's path (in the network or in the
hosts).</para>
</refsection>
<refsection xml:id="trying_different_data_patterns">
<info>
<title>TRYING DIFFERENT DATA PATTERNS</title>
</info>
<para>The (inter)network layer should never treat packets
differently depending on the data contained in the data
portion. Unfortunately, data-dependent problems have been known
to sneak into networks and remain undetected for long periods
of time. In many cases the particular pattern that will have
problems is something that doesn't have sufficient
“transitions”, such as all ones or all zeros, or a pattern
right at the edge, such as almost all zeros. It isn't
necessarily enough to specify a data pattern of all zeros (for
example) on the command line because the pattern that is of
interest is at the data link level, and the relationship
between what you type and what the controllers transmit can be
complicated.</para>
<para>This means that if you have a data-dependent problem you
will probably have to do a lot of testing to find it. If you
are lucky, you may manage to find a file that either can't be
sent across your network or that takes much longer to transfer
than other similar length files. You can then examine this file
for repeated patterns that you can test using the
<option>-p</option> option of
<command>ping</command>.</para>
</refsection>
<refsection xml:id="ttl_details">
<info>
<title>TTL DETAILS</title>
</info>
<para>The TTL value of an IP packet represents the maximum
number of IP routers that the packet can go through before
being thrown away. In current practice you can expect each
router in the Internet to decrement the TTL field by exactly
one.</para>
<para>The TCP/IP specification states that the TTL field for
TCP packets should be set to 60, but many systems use smaller
values (4.3 BSD uses 30, 4.2 used 15).</para>
<para>The maximum possible value of this field is 255, and most
Unix systems set the TTL field of ICMP ECHO_REQUEST packets to
255. This is why you will find you can “ping” some hosts, but
not reach them with
<citerefentry>
<refentrytitle>telnet</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry> or
<citerefentry>
<refentrytitle>ftp</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>.</para>
<para>In normal operation ping prints the TTL value from the
packet it receives. When a remote system receives a ping
packet, it can do one of three things with the TTL field in its
response:</para>
<variablelist remap="TP">
<varlistentry>
<listitem>
<para>• Not change it; this is what Berkeley Unix systems
did before the 4.3BSD Tahoe release. In this case the TTL
value in the received packet will be 255 minus the number
of routers in the round-trip path.</para>
</listitem>
</varlistentry>
<varlistentry>
<listitem>
<para>• Set it to 255; this is what current Berkeley Unix
systems do. In this case the TTL value in the received
packet will be 255 minus the number of routers in the
path
<emphasis remap="B">from</emphasis> the remote system
<emphasis remap="B">to</emphasis> the
<command>ping</command>ing host.</para>
</listitem>
</varlistentry>
<varlistentry>
<listitem>
<para>• Set it to some other value. Some machines use the
same value for ICMP packets that they use for TCP
packets, for example either 30 or 60. Others may use
completely wild values.</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection xml:id="bugs">
<info>
<title>BUGS</title>
</info>
<variablelist remap="TP">
<varlistentry>
<listitem>
<para>• Many Hosts and Gateways ignore the RECORD_ROUTE
option.</para>
</listitem>
</varlistentry>
<varlistentry>
<listitem>
<para>• The maximum IP header length is too small for
options like RECORD_ROUTE to be completely useful.
There's not much that can be done about this,
however.</para>
</listitem>
</varlistentry>
<varlistentry>
<listitem>
<para>• Flood pinging is not recommended in general, and
flood pinging the broadcast address should only be done
under very controlled conditions.</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection xml:id="see_also">
<info>
<title>SEE ALSO</title>
</info>
<para>
<citerefentry>
<refentrytitle>ip</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>ss</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>.</para>
</refsection>
<refsection xml:id="history">
<info>
<title>HISTORY</title>
</info>
<para>The
<command>ping</command> command appeared in 4.3BSD.</para>
<para>The version described here is its descendant specific to
Linux.</para>
<para>As of version s20150815, the
<emphasis remap="B">ping6</emphasis> binary doesn't exist
anymore. It has been merged into
<command>ping</command>. Creating a symlink named
<emphasis remap="B">ping6</emphasis> pointing to
<command>ping</command> will result in the same functionality as
before.</para>
</refsection>
<refsection xml:id="security">
<info>
<title>SECURITY</title>
</info>
<para>
<command>ping</command> requires CAP_NET_RAW capability to be
executed 1) if the program is used for non-echo queries (See
<option>-N</option> option), or 2) if kernel does not support
non-raw ICMP sockets, or 3) if the user is not allowed to
create an ICMP echo socket. The program may be used as set-uid
root.</para>
</refsection>
<refsection xml:id="availability">
<info>
<title>AVAILABILITY</title>
</info>
<para>
<command>ping</command> is part of
<emphasis remap="I">iputils</emphasis> package.</para>
</refsection>
</refentry>
Radix cross Linux
The main Radix cross Linux repository contains the build scripts of packages, which have the most complete and common functionality for desktop machines
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