X-Git-Url: https://git.saurik.com/apple/network_cmds.git/blobdiff_plain/2b484d24084b903459c5b416c06cd77b48c748b9..5902acfc600aa7d331608b1286d6af0b21f6a7ba:/ping.tproj/ping.8

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@@ -1,519 +1,554 @@
-.\" Copyright (c) 1985, 1991, 1993
-.\"	The Regents of the University of California.  All rights reserved.
-.\"
-.\" Redistribution and use in source and binary forms, with or without
-.\" modification, are permitted provided that the following conditions
-.\" are met:
-.\" 1. Redistributions of source code must retain the above copyright
-.\"    notice, this list of conditions and the following disclaimer.
-.\" 2. Redistributions in binary form must reproduce the above copyright
-.\"    notice, this list of conditions and the following disclaimer in the
-.\"    documentation and/or other materials provided with the distribution.
-.\" 4. Neither the name of the University nor the names of its contributors
-.\"    may be used to endorse or promote products derived from this software
-.\"    without specific prior written permission.
-.\"
-.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
-.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
-.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-.\" SUCH DAMAGE.
-.\"
-.\"     @(#)ping.8	8.2 (Berkeley) 12/11/93
-.\" $FreeBSD: /repoman/r/ncvs/src/sbin/ping/ping.8,v 1.51 2004/04/09 19:58:34 markm Exp $
-.\"
-.Dd October 2, 2002
-.Dt PING 8
-.Os
-.Sh NAME
-.Nm ping
-.Nd send
-.Tn ICMP ECHO_REQUEST
-packets to network hosts
-.Sh SYNOPSIS
-.Nm
-.Op Fl AaDdfnoQqRrv
-.Op Fl c Ar count
-.Op Fl i Ar wait
-.Op Fl l Ar preload
-.Op Fl M Cm mask | time
-.Op Fl m Ar ttl
-.Op Fl P Ar policy
-.Op Fl p Ar pattern
-.Op Fl S Ar src_addr
-.Op Fl s Ar packetsize
-.Op Fl t Ar timeout
-.Op Fl z Ar tos
-.Ar host
-.Nm
-.Op Fl AaDdfLnoQqRrv
-.Op Fl c Ar count
-.Op Fl I Ar iface
-.Op Fl i Ar wait
-.Op Fl l Ar preload
-.Op Fl M Cm mask | time
-.Op Fl m Ar ttl
-.Op Fl P Ar policy
-.Op Fl p Ar pattern
-.Op Fl S Ar src_addr
-.Op Fl s Ar packetsize
-.Op Fl T Ar ttl
-.Op Fl t Ar timeout
-.Op Fl z Ar tos
-.Ar mcast-group
-.Sh DESCRIPTION
-The
-.Nm
-utility uses the
-.Tn ICMP
-.No protocol Ap s mandatory
-.Tn ECHO_REQUEST
-datagram to elicit an
-.Tn ICMP ECHO_RESPONSE
-from a host or gateway.
-.Tn ECHO_REQUEST
-datagrams
-.Pq Dq pings
-have an IP and
-.Tn ICMP
-header, followed by a
-.Dq struct timeval
-and then an arbitrary number of
-.Dq pad
-bytes used to fill out the packet.
-The options are as follows:
-.Bl -tag -width indent
-.It Fl A
-Audible.
-Output a bell
-.Tn ( ASCII
-0x07)
-character when no packet is received before the next packet
-is transmitted.
-To cater for round-trip times that are longer than the interval
-between transmissions, further missing packets cause a bell only
-if the maximum number of unreceived packets has increased.
-.It Fl a
-Audible.
-Include a bell
-.Tn ( ASCII
-0x07)
-character in the output when any packet is received.
-This option is ignored
-if other format options are present.
-.It Fl c Ar count
-Stop after sending
-(and receiving)
-.Ar count
-.Tn ECHO_RESPONSE
-packets.
-If this option is not specified,
-.Nm
-will operate until interrupted.
-.It Fl D
-Set the Don't Fragment bit.
-.It Fl d
-Set the
-.Dv SO_DEBUG
-option on the socket being used.
-.It Fl f
-Flood ping.
-Outputs packets as fast as they come back or one hundred times per second,
-whichever is more.
-For every
-.Tn ECHO_REQUEST
-sent a period
-.Dq .\&
-is printed, while for every
-.Tn ECHO_REPLY
-received a backspace is printed.
-This provides a rapid display of how many packets are being dropped.
-Only the super-user may use this option.
-.Bf -emphasis
-This can be very hard on a network and should be used with caution.
-.Ef
-.It Fl I Ar iface
-Source multicast packets with the given interface address.
-This flag only applies if the ping destination is a multicast address.
-.It Fl i Ar wait
-Wait
-.Ar wait
-seconds
-.Em between sending each packet .
-The default is to wait for one second between each packet.
-The wait time may be fractional, but only the super-user may specify
-values less than 1 second.
-This option is incompatible with the
-.Fl f
-option.
-.It Fl L
-Suppress loopback of multicast packets.
-This flag only applies if the ping destination is a multicast address.
-.It Fl l Ar preload
-If
-.Ar preload
-is specified,
-.Nm
-sends that many packets as fast as possible before falling into its normal
-mode of behavior.
-Only the super-user may use this option.
-.It Fl M Cm mask | time
-Use
-.Dv ICMP_MASKREQ
-or
-.Dv ICMP_TSTAMP
-instead of
-.Dv ICMP_ECHO .
-For
-.Cm mask ,
-print the netmask of the remote machine.
-Set the
-.Va net.inet.icmp.maskrepl
-MIB variable to enable
-.Dv ICMP_MASKREPLY .
-For
-.Cm time ,
-print the origination, reception and transmission timestamps.
-.It Fl m Ar ttl
-Set the IP Time To Live for outgoing packets.
-If not specified, the kernel uses the value of the
-.Va net.inet.ip.ttl
-MIB variable.
-.It Fl n
-Numeric output only.
-No attempt will be made to lookup symbolic names for host addresses.
-.It Fl o
-Exit successfully after receiving one reply packet.
-.It Fl P Ar policy
-.Ar policy
-specifies IPsec policy for the ping session.
-For details please refer to
-.Xr ipsec 4
-and
-.Xr ipsec_set_policy 3 .
-.It Fl p Ar pattern
-You may specify up to 16
-.Dq pad
-bytes to fill out the packet you send.
-This is useful for diagnosing data-dependent problems in a network.
-For example,
-.Dq Li \-p ff
-will cause the sent packet to be filled with all
-ones.
-.It Fl Q
-Somewhat quiet output.
-.No Don Ap t
-display ICMP error messages that are in response to our query messages.
-Originally, the
-.Fl v
-flag was required to display such errors, but
-.Fl v
-displays all ICMP error messages.
-On a busy machine, this output can be overbearing.
-Without the
-.Fl Q
-flag,
-.Nm
-prints out any ICMP error messages caused by its own ECHO_REQUEST
-messages.
-.It Fl q
-Quiet output.
-Nothing is displayed except the summary lines at startup time and
-when finished.
-.It Fl R
-Record route.
-Includes the
-.Tn RECORD_ROUTE
-option in the
-.Tn ECHO_REQUEST
-packet and displays
-the route buffer on returned packets.
-Note that the IP header is only large enough for nine such routes;
-the
-.Xr traceroute 8
-command is usually better at determining the route packets take to a
-particular destination.
-If more routes come back than should, such as due to an illegal spoofed
-packet, ping will print the route list and then truncate it at the correct
-spot.
-Many hosts ignore or discard the
-.Tn RECORD_ROUTE
-option.
-.It Fl 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 no route through it
-(e.g., after the interface was dropped by
-.Xr routed 8 ) .
-.It Fl S Ar src_addr
-Use the following IP address as the source address in outgoing packets.
-On hosts with more than one IP address, this option can be used to
-force the source address to be something other than the IP address
-of the interface the probe packet is sent on.
-If the IP address
-is not one of this machine's interface addresses, an error is
-returned and nothing is sent.
-.It Fl s Ar packetsize
-Specify the number of data bytes to be sent.
-The default is 56, which translates into 64
-.Tn ICMP
-data bytes when combined
-with the 8 bytes of
-.Tn ICMP
-header data.
-.It Fl T Ar ttl
-Set the IP Time To Live for multicasted packets.
-This flag only applies if the ping destination is a multicast address.
-.It Fl t Ar timeout
-Specify a timeout, in seconds, before ping exits regardless of how
-many packets have been received.
-.It Fl v
-Verbose output.
-.Tn ICMP
-packets other than
-.Tn ECHO_RESPONSE
-that are received are listed.
-.It Fl z Ar tos
-Use the specified type of service.
-.El
-.Pp
-When using
-.Nm
-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
-.Dq 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 round-trip time statistics.
-When the specified number of packets have been sent
-(and received)
-or if the program is terminated with a
-.Dv SIGINT ,
-a brief summary is displayed, showing the number of packets sent and
-received, and the minimum, mean, maximum, and standard deviation of
-the round-trip times.
-.Pp
-If
-.Nm
-receives a
-.Dv SIGINFO
-(see the
-.Cm status
-argument for
-.Xr stty 1 )
-signal, the current number of packets sent and received, and the
-minimum, mean, and maximum of the round-trip times will be written to
-the standard error output.
-.Pp
-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
-.Nm
-during normal operations or from automated scripts.
-.Sh ICMP PACKET DETAILS
-An IP header without options is 20 bytes.
-An
-.Tn ICMP
-.Tn ECHO_REQUEST
-packet contains an additional 8 bytes worth of
-.Tn ICMP
-header followed by an arbitrary amount of data.
-When a
-.Ar packetsize
-is given, this indicated 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
-.Tn ICMP
-.Tn ECHO_REPLY
-will always be 8 bytes more than the requested data space
-(the
-.Tn ICMP
-header).
-.Pp
-If the data space is at least eight bytes large,
-.Nm
-uses the first eight bytes of this space to include a timestamp which
-it uses in the computation of round trip times.
-If less than eight bytes of pad are specified, no round trip times are
-given.
-.Sh DUPLICATE AND DAMAGED PACKETS
-The
-.Nm
-utility will report duplicate and damaged packets.
-Duplicate packets should never occur when pinging a unicast address,
-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.
-Duplicates are expected when pinging a broadcast or multicast address,
-since they are not really duplicates but replies from different hosts
-to the same request.
-.Pp
-Damaged packets are obviously serious cause for alarm and often
-indicate broken hardware somewhere in the
-.Nm
-packet's path (in the network or in the hosts).
-.Sh TRYING DIFFERENT DATA PATTERNS
-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 does not have sufficient
-.Dq transitions ,
-such as all ones or all zeros, or a pattern right at the edge, such as
-almost all zeros.
-It is not
-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.
-.Pp
-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
-cannot
-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
-.Fl p
-option of
-.Nm .
-.Sh TTL DETAILS
-The
-.Tn 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
-.Tn TTL
-field by exactly one.
-.Pp
-The
-.Tn TCP/IP
-specification recommends setting the
-.Tn TTL
-field for
-.Tn IP
-packets to 64, but many systems use smaller values
-.No ( Bx 4.3
-uses 30,
-.Bx 4.2
-used 15).
-.Pp
-The maximum possible value of this field is 255, and most
-.Ux
-systems set
-the
-.Tn TTL
-field of
-.Tn ICMP ECHO_REQUEST
-packets to 255.
-This is why you will find you can
-.Dq ping
-some hosts, but not reach them with
-.Xr telnet 1
-or
-.Xr ftp 1 .
-.Pp
-In normal operation
-.Nm
-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
-.Tn TTL
-field in its response:
-.Bl -bullet
-.It
-Not change it; this is what
-.Bx
-systems did before the
-.Bx 4.3 tahoe
-release.
-In this case the
-.Tn TTL
-value in the received packet will be 255 minus the
-number of routers in the round-trip path.
-.It
-Set it to 255; this is what current
-.Bx
-systems do.
-In this case the
-.Tn TTL
-value in the received packet will be 255 minus the
-number of routers in the path
-.Em from
-the remote system
-.Em to
-the
-.Nm Ns Em ing
-host.
-.It
-Set it to some other value.
-Some machines use the same value for
-.Tn ICMP
-packets that they use for
-.Tn TCP
-packets, for example either 30 or 60.
-Others may use completely wild values.
-.El
-.Sh RETURN VALUES
-The
-.Nm
-utility returns an exit status of zero if at least one response was
-heard from the specified
-.Ar host ;
-a status of two if the transmission was successful but no responses
-were received; or another value
-(from
-.In sysexits.h )
-if an error occurred.
-.Sh SEE ALSO
-.Xr netstat 1 ,
-.Xr ifconfig 8 ,
-.Xr routed 8 ,
-.Xr traceroute 8
-.Sh HISTORY
-The
-.Nm
-utility appeared in
-.Bx 4.3 .
-.Sh AUTHORS
-The original
-.Nm
-utility was written by
-.An Mike Muuss
-while at the US Army Ballistics
-Research Laboratory.
-.Sh BUGS
-Many Hosts and Gateways ignore the
-.Tn RECORD_ROUTE
-option.
-.Pp
-The maximum IP header length is too small for options like
-.Tn RECORD_ROUTE
-to be completely useful.
-.No There Ap s
-not much that can be done about this, however.
-.Pp
-Flood pinging is not recommended in general, and flood pinging the
-broadcast address should only be done under very controlled conditions.
-.Pp
-The
-.Fl v
-option is not worth much on busy hosts.
+.\" Copyright (c) 1985, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)ping.8	8.2 (Berkeley) 12/11/93
+.\" $FreeBSD: src/sbin/ping/ping.8,v 1.51.8.2 2006/08/10 10:48:21 glebius Exp $
+.\"
+.Dd April 4, 2006
+.Dt PING 8
+.Os
+.Sh NAME
+.Nm ping
+.Nd send
+.Tn ICMP ECHO_REQUEST
+packets to network hosts
+.Sh SYNOPSIS
+.Nm
+.Op Fl AaDdfnoQqRrv
+.Op Fl b Ar boundif
+.Op Fl c Ar count
+.Op Fl G Ar sweepmaxsize
+.Op Fl g Ar sweepminsize
+.Op Fl h Ar sweepincrsize
+.Op Fl i Ar wait
+.Op Fl l Ar preload
+.Op Fl M Cm mask | time
+.Op Fl m Ar ttl
+.Op Fl P Ar policy
+.Op Fl p Ar pattern
+.Op Fl S Ar src_addr
+.Op Fl s Ar packetsize
+.Op Fl t Ar timeout
+.Op Fl W Ar waittime
+.Op Fl z Ar tos
+.Ar host
+.Nm
+.Op Fl AaDdfLnoQqRrv
+.Op Fl b Ar boundif
+.Op Fl c Ar count
+.Op Fl I Ar iface
+.Op Fl i Ar wait
+.Op Fl l Ar preload
+.Op Fl M Cm mask | time
+.Op Fl m Ar ttl
+.Op Fl P Ar policy
+.Op Fl p Ar pattern
+.Op Fl S Ar src_addr
+.Op Fl s Ar packetsize
+.Op Fl T Ar ttl
+.Op Fl t Ar timeout
+.Op Fl W Ar waittime
+.Op Fl z Ar tos
+.Ar mcast-group
+.Sh DESCRIPTION
+The
+.Nm
+utility uses the
+.Tn ICMP
+.No protocol Ap s mandatory
+.Tn ECHO_REQUEST
+datagram to elicit an
+.Tn ICMP ECHO_RESPONSE
+from a host or gateway.
+.Tn ECHO_REQUEST
+datagrams
+.Pq Dq pings
+have an IP and
+.Tn ICMP
+header, followed by a
+.Dq struct timeval
+and then an arbitrary number of
+.Dq pad
+bytes used to fill out the packet.
+The options are as follows:
+.Bl -tag -width indent
+.It Fl A
+Audible.
+Output a bell
+.Tn ( ASCII
+0x07)
+character when no packet is received before the next packet
+is transmitted.
+To cater for round-trip times that are longer than the interval
+between transmissions, further missing packets cause a bell only
+if the maximum number of unreceived packets has increased.
+.It Fl a
+Audible.
+Include a bell
+.Tn ( ASCII
+0x07)
+character in the output when any packet is received.
+This option is ignored
+if other format options are present.
+.It Fl b Ar boundif
+Bind the socket to interface
+.Ar boundif
+for sending.
+.It Fl c Ar count
+Stop after sending
+(and receiving)
+.Ar count
+.Tn ECHO_RESPONSE
+packets.
+If this option is not specified,
+.Nm
+will operate until interrupted.
+If this option is specified in conjunction with ping sweeps,
+each sweep will consist of
+.Ar count
+packets.
+.It Fl D
+Set the Don't Fragment bit.
+.It Fl d
+Set the
+.Dv SO_DEBUG
+option on the socket being used.
+.It Fl f
+Flood ping.
+Outputs packets as fast as they come back or one hundred times per second,
+whichever is more.
+For every
+.Tn ECHO_REQUEST
+sent a period
+.Dq .\&
+is printed, while for every
+.Tn ECHO_REPLY
+received a backspace is printed.
+This provides a rapid display of how many packets are being dropped.
+Only the super-user may use this option.
+.Bf -emphasis
+This can be very hard on a network and should be used with caution.
+.Ef
+.It Fl G Ar sweepmaxsize
+Specify the maximum size of
+.Tn ICMP
+payload when sending sweeping pings.
+This option is required for ping sweeps. 
+.It Fl g Ar sweepminsize
+Specify the size of
+.Tn ICMP
+payload to start with when sending sweeping pings. 
+The default value is 0.
+.It Fl h Ar sweepincrsize
+Specify the number of bytes to increment the size of
+.Tn ICMP
+payload after
+each sweep when sending sweeping pings. The default value is 1.
+.It Fl I Ar iface
+Source multicast packets with the given interface address.
+This flag only applies if the ping destination is a multicast address.
+.It Fl i Ar wait
+Wait
+.Ar wait
+seconds
+.Em between sending each packet .
+The default is to wait for one second between each packet.
+The wait time may be fractional, but only the super-user may specify
+values less than 1 second.
+This option is incompatible with the
+.Fl f
+option.
+.It Fl L
+Suppress loopback of multicast packets.
+This flag only applies if the ping destination is a multicast address.
+.It Fl l Ar preload
+If
+.Ar preload
+is specified,
+.Nm
+sends that many packets as fast as possible before falling into its normal
+mode of behavior.
+Only the super-user may use this option.
+.It Fl M Cm mask | time
+Use
+.Dv ICMP_MASKREQ
+or
+.Dv ICMP_TSTAMP
+instead of
+.Dv ICMP_ECHO .
+For
+.Cm mask ,
+print the netmask of the remote machine.
+Set the
+.Va net.inet.icmp.maskrepl
+MIB variable to enable
+.Dv ICMP_MASKREPLY .
+For
+.Cm time ,
+print the origination, reception and transmission timestamps.
+.It Fl m Ar ttl
+Set the IP Time To Live for outgoing packets.
+If not specified, the kernel uses the value of the
+.Va net.inet.ip.ttl
+MIB variable.
+.It Fl n
+Numeric output only.
+No attempt will be made to lookup symbolic names for host addresses.
+.It Fl o
+Exit successfully after receiving one reply packet.
+.It Fl P Ar policy
+.Ar policy
+specifies IPsec policy for the ping session.
+For details please refer to
+.Xr ipsec 4
+and
+.Xr ipsec_set_policy 3 .
+.It Fl p Ar pattern
+You may specify up to 16
+.Dq pad
+bytes to fill out the packet you send.
+This is useful for diagnosing data-dependent problems in a network.
+For example,
+.Dq Li \-p ff
+will cause the sent packet to be filled with all
+ones.
+.It Fl Q
+Somewhat quiet output.
+.No Don Ap t
+display ICMP error messages that are in response to our query messages.
+Originally, the
+.Fl v
+flag was required to display such errors, but
+.Fl v
+displays all ICMP error messages.
+On a busy machine, this output can be overbearing.
+Without the
+.Fl Q
+flag,
+.Nm
+prints out any ICMP error messages caused by its own ECHO_REQUEST
+messages.
+.It Fl q
+Quiet output.
+Nothing is displayed except the summary lines at startup time and
+when finished.
+.It Fl R
+Record route.
+Includes the
+.Tn RECORD_ROUTE
+option in the
+.Tn ECHO_REQUEST
+packet and displays
+the route buffer on returned packets.
+Note that the IP header is only large enough for nine such routes;
+the
+.Xr traceroute 8
+command is usually better at determining the route packets take to a
+particular destination.
+If more routes come back than should, such as due to an illegal spoofed
+packet, ping will print the route list and then truncate it at the correct
+spot.
+Many hosts ignore or discard the
+.Tn RECORD_ROUTE
+option.
+.It Fl 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 no route through it
+(e.g., after the interface was dropped by
+.Xr routed 8 ) .
+.It Fl S Ar src_addr
+Use the following IP address as the source address in outgoing packets.
+On hosts with more than one IP address, this option can be used to
+force the source address to be something other than the IP address
+of the interface the probe packet is sent on.
+If the IP address
+is not one of this machine's interface addresses, an error is
+returned and nothing is sent.
+.It Fl s Ar packetsize
+Specify the number of data bytes to be sent.
+The default is 56, which translates into 64
+.Tn ICMP
+data bytes when combined
+with the 8 bytes of
+.Tn ICMP
+header data.
+This option cannot be used with ping sweeps.
+.It Fl T Ar ttl
+Set the IP Time To Live for multicasted packets.
+This flag only applies if the ping destination is a multicast address.
+.It Fl t Ar timeout
+Specify a timeout, in seconds, before ping exits regardless of how
+many packets have been received.
+.It Fl v
+Verbose output.
+.Tn ICMP
+packets other than
+.Tn ECHO_RESPONSE
+that are received are listed.
+.It Fl W Ar waittime
+Time in milliseconds to wait for a reply for each packet sent.
+If a reply arrives later, the packet is not printed as replied, but
+considered as replied when calculating statistics.
+.It Fl z Ar tos
+Use the specified type of service.
+.El
+.Pp
+When using
+.Nm
+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
+.Dq 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 round-trip time statistics.
+When the specified number of packets have been sent
+(and received)
+or if the program is terminated with a
+.Dv SIGINT ,
+a brief summary is displayed, showing the number of packets sent and
+received, and the minimum, mean, maximum, and standard deviation of
+the round-trip times.
+.Pp
+If
+.Nm
+receives a
+.Dv SIGINFO
+(see the
+.Cm status
+argument for
+.Xr stty 1 )
+signal, the current number of packets sent and received, and the
+minimum, mean, and maximum of the round-trip times will be written to
+the standard error output.
+.Pp
+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
+.Nm
+during normal operations or from automated scripts.
+.Sh ICMP PACKET DETAILS
+An IP header without options is 20 bytes.
+An
+.Tn ICMP
+.Tn ECHO_REQUEST
+packet contains an additional 8 bytes worth of
+.Tn ICMP
+header followed by an arbitrary amount of data.
+When a
+.Ar packetsize
+is given, this indicated 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
+.Tn ICMP
+.Tn ECHO_REPLY
+will always be 8 bytes more than the requested data space
+(the
+.Tn ICMP
+header).
+.Pp
+If the data space is at least eight bytes large,
+.Nm
+uses the first eight bytes of this space to include a timestamp which
+it uses in the computation of round trip times.
+If less than eight bytes of pad are specified, no round trip times are
+given.
+.Sh DUPLICATE AND DAMAGED PACKETS
+The
+.Nm
+utility will report duplicate and damaged packets.
+Duplicate packets should never occur when pinging a unicast address,
+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.
+Duplicates are expected when pinging a broadcast or multicast address,
+since they are not really duplicates but replies from different hosts
+to the same request.
+.Pp
+Damaged packets are obviously serious cause for alarm and often
+indicate broken hardware somewhere in the
+.Nm
+packet's path (in the network or in the hosts).
+.Sh TRYING DIFFERENT DATA PATTERNS
+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 does not have sufficient
+.Dq transitions ,
+such as all ones or all zeros, or a pattern right at the edge, such as
+almost all zeros.
+It is not
+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.
+.Pp
+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
+cannot
+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
+.Fl p
+option of
+.Nm .
+.Sh TTL DETAILS
+The
+.Tn 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
+.Tn TTL
+field by exactly one.
+.Pp
+The
+.Tn TCP/IP
+specification recommends setting the
+.Tn TTL
+field for
+.Tn IP
+packets to 64, but many systems use smaller values
+.No ( Bx 4.3
+uses 30,
+.Bx 4.2
+used 15).
+.Pp
+The maximum possible value of this field is 255, and most
+.Ux
+systems set
+the
+.Tn TTL
+field of
+.Tn ICMP ECHO_REQUEST
+packets to 255.
+This is why you will find you can
+.Dq ping
+some hosts, but not reach them with
+.Xr telnet 1
+or
+.Xr ftp 1 .
+.Pp
+In normal operation
+.Nm
+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
+.Tn TTL
+field in its response:
+.Bl -bullet
+.It
+Not change it; this is what
+.Bx
+systems did before the
+.Bx 4.3 tahoe
+release.
+In this case the
+.Tn TTL
+value in the received packet will be 255 minus the
+number of routers in the round-trip path.
+.It
+Set it to 255; this is what current
+.Bx
+systems do.
+In this case the
+.Tn TTL
+value in the received packet will be 255 minus the
+number of routers in the path
+.Em from
+the remote system
+.Em to
+the
+.Nm Ns Em ing
+host.
+.It
+Set it to some other value.
+Some machines use the same value for
+.Tn ICMP
+packets that they use for
+.Tn TCP
+packets, for example either 30 or 60.
+Others may use completely wild values.
+.El
+.Sh RETURN VALUES
+The
+.Nm
+utility returns an exit status of zero if at least one response was
+heard from the specified
+.Ar host ;
+a status of two if the transmission was successful but no responses
+were received; or another value
+(from
+.In sysexits.h )
+if an error occurred.
+.Sh SEE ALSO
+.Xr netstat 1 ,
+.Xr ifconfig 8 ,
+.Xr routed 8 ,
+.Xr traceroute 8
+.Sh HISTORY
+The
+.Nm
+utility appeared in
+.Bx 4.3 .
+.Sh AUTHORS
+The original
+.Nm
+utility was written by
+.An Mike Muuss
+while at the US Army Ballistics
+Research Laboratory.
+.Sh BUGS
+Many Hosts and Gateways ignore the
+.Tn RECORD_ROUTE
+option.
+.Pp
+The maximum IP header length is too small for options like
+.Tn RECORD_ROUTE
+to be completely useful.
+.No There Ap s
+not much that can be done about this, however.
+.Pp
+Flood pinging is not recommended in general, and flood pinging the
+broadcast address should only be done under very controlled conditions.
+.Pp
+The
+.Fl v
+option is not worth much on busy hosts.