ping8iputils-&snapshot;ping, ping6send ICMP ECHO_REQUEST to network hostsping-c -m -i -l -p -s -t -w -F -I -M -N -Q -S -T -W DESCRIPTIONOPTIONS
use
Stop after sending
option,
Allocate and set 20 bit flow label on echo request packets.
(Only
Wait
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.
If
Send ICMPv6 Node Information Queries (RFC4620), instead of Echo Request.
Queries for Node Names.Queries for IPv6 Addresses. There are several IPv6 specific flags.
Request IPv6 global-scope addresses.Request IPv6 site-local addresses.Request IPv6 link-local addresses.Request IPv6 addresses on other interfaces.Queries for IPv4 Addresses. There is one IPv4 specific flag.
Request IPv4 addresses on other interfaces.IPv6 subject address.IPv4 subject address.Subject name. If it contains more than one dot,
fully-qualified domain name is assumed.Subject name. Fully-qualified domain name is
always assumed.
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, will cause the sent packet
to be filled with all ones.
Set Quality of Service -related bits in ICMP datagrams.
-s
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
Set socket sndbuf. If not specified, it is selected to buffer
not more than one packet.
-t
Set the IP Time to Live.
-T
Set special IP timestamp options.
-M
Select Path MTU Discovery strategy.
Print full user-to-user latency (the old behaviour). Normally
Verbose output.
Show version and exit.
-w
Specify a timeout, in seconds, before
packet are sent, it waits either for
expire or until
probes are answered or for some error notification from network.
-W
Time to wait for a response, in seconds. The option affects only timeout
in absense of any responses, otherwise
When using
If
and
are both specified, and fewer than
packets are received by the time the
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.
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
ICMP PACKET DETAILS
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
If the data space is at least of size of DUPLICATE AND DAMAGED PACKETS
Damaged packets are obviously serious cause for alarm and often
indicate broken hardware somewhere in the
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 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.
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
TTL DETAILS
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.
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).
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
or
.
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:
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.
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
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.
BUGS
Many Hosts and Gateways ignore the RECORD_ROUTE option.
The maximum IP header length is too small for options like
RECORD_ROUTE to be completely useful.
There's not much that that can be done about this, however.
Flood pinging is not recommended in general, and flood pinging the
broadcast address should only be done under very controlled conditions.
SEE ALSO,
.
HISTORY
The
The version described here is its descendant specific to Linux.
SECURITYAVAILABILITY
http://www.skbuff.net/iputils/iputils-current.tar.bz2.
COPYING
Copyright (c) 1989 The Regents of the University of California.
All rights reserved.
This code is derived from software contributed to Berkeley by
Mike Muuss.
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.
3. All advertising materials mentioning features or use of this software
must display the following acknowledgement:
This product includes software developed by the University of
California, Berkeley and its contributors.
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.
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