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2PING(1) User Contributed Perl Documentation 2PING(1)
NAME
2ping - A bi-directional ping client/listener
SYNOPSIS
2ping [ options ] --listen | host/IP
DESCRIPTION
2ping is a bi-directional ping utility. It uses 3-way pings (akin to
TCP SYN, SYN/ACK, ACK) and after-the-fact state comparison between a
2ping listener and a 2ping client to determine which direction packet
loss occurs.
To use 2ping, start a listener on a known stable network host. The
relative network stability of the 2ping listener host should not be in
question, because while 2ping can determine whether packet loss is
occurring inbound or outbound relative to an endpoint, that will not
help you determine the cause if both of the endpoints are in question.
Once the listener is started, start 2ping in client mode and tell it to
connect to the listener. The ends will begin pinging each other and
displaying network statistics. If packet loss occurs, 2ping will wait
a few seconds (default 10, configurable with -w) before comparing notes
between the two endpoints to determine which direction the packet loss
is occurring.
To quit 2ping on the client or listener ends, enter ^C, and a list of
statistics will be displayed. To get a short inline display of
statistics without quitting, send the process a QUIT signal (yes,
that's the opposite of what you would think, but it's in line with the
normal ping utility).
OPTIONS
ping-compatible options:
-a Audible ping.
-A Adaptive ping. A new client ping request is sent as soon as a
client ping response is received. If a ping response is not
received within the interval period, a new ping request is sent.
Minimal interval is 200msec for not super-user. On networks with
low rtt this mode is essentially equivalent to flood mode.
2ping-specific notes: This behavior is somewhat different to the
nature of ping's adaptive ping, but the result is roughly the same.
-c count
Stop after sending count ping requests.
2ping-specific notes: This option behaves slightly differently from
ping. If both -c and -w are specified, satisfaction of -c will
cause an exit first. Also, internally, 2ping exits just before
sending count+1 pings, to give time for the ping to complete.
-f Flood ping. For every ping sent a period "." is printed, while for
ever ping received a backspace is printed. This provides a rapid
display of how many pings are being dropped. If interval is not
given, it sets interval to zero and outputs pings 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.
2ping-specific notes: Detected outbound/inbound loss responses are
printed as ">" and "<", respectively. Receive errors are printed
as "E". Due to the asynchronous nature of 2ping, successful
responses (backspaces) may overwrite these loss and error
characters.
-i interval
Wait interval seconds between sending each ping. The default is to
wait for one second between each ping normally, or not to wait in
flood mode. Only super-user may set interval to values less 0.2
seconds.
-I interface IP
Set source IP address. When pinging IPv6 link-local address this
option is required. When in listener mode, this option may be
specified multiple to bind to multiple IP addresses. When in
client mode, this option may only be specified once, and all
outbound pings will be bound to this source IP.
2ping-specific notes: This option only takes an IP address, not a
device name. Note that in listener mode, if the machine has an
interface with multiple IP addresses and an request comes in via a
sub IP, the reply still leaves via the interface's main IP. So
this option must be used if you would like to respond via an
interface's sub-IP.
-l preload
If preload is specified, 2ping sends that many packets not waiting
for reply. Only the super-user may select preload more than 3.
-p pattern
You may specify up to 16 "pad" bytes to fill out the packets you
send. This is useful for diagnosing data-dependent problems in a
network. For example, -p ff will cause the sent packet pad area to
be filled with all ones.
2ping-specific notes: This pads the portion of the packet that does
not contain the active payload data. If the active payload data is
larger than the minimum packet size (--min-packet-size=min), no
padding will be sent.
-q Quiet output. Nothing is displayed except the summary lines at
startup time and when finished.
-s packetsize
ping compatibility, this will set --min-packet-size to this plus 8
bytes.
-v Verbose output. In 2ping, this prints decodes of packets that are
sent and received.
-V Show version and exit.
-w deadline
Specify a timeout, in seconds, before 2ping exits regardless of how
many pings have been sent or received. Due to blocking, this may
occur up to one second after the deadline specified.
2ping-specific notes: This option behaves slightly differently from
ping. If both -c and -w are specified, satisfaction of -c will
cause an exit first.
2ping-specific options:
-?, --help
Print a synposis and exit.
-6, --ipv6
Bind/connect as IPv6.
--auth=key
Set a shared key, send cryptographic hashes with each packet, and
require cryptographic hashes from peer packets signed with the same
shared key.
--auth-digest=digest
When --auth is used, specify the digest type to compute the
cryptographic hash. Valid options are hmac-md5 (default),
hmac-sha1 and hmac-sha256. hmac-md5 requires Digest::MD5, and the
SHA digests require Digest::SHA.
--debug
Print (lots of) debugging information.
--inquire-wait=secs
Wait at least secs seconds before inquiring about a lost packet.
Default is 10 seconds. UDP packets can arrive delayed or out of
order, so it is best to give it some time before inquiring about a
lost packet.
--listen
Start as a listener. The listener will not send out ping requests
at regular intervals, and will instead wait for the far end to
initiate ping requests. A listener is required as the remote end
for a client.
--min-packet-size=min
Set the minimum total payload size to min bytes, default 128. If
the payload is smaller than min bytes, padding will be added to the
end of the packet.
--max-packet-size=max
Set the maximum total payload size to max bytes, default 512,
absolute minimum 64. If the payload is larger than max bytes,
information will be rearranged and sent in future packets when
possible.
--no-3way
Do not perform 3-way pings. Used most often when combined with
--listen, as the listener is usually the one to determine whether a
ping reply should become a 3-way ping.
Strictly speaking, a 3-way ping is not necessary for determining
directional packet loss between the client and the listener.
However, the extra leg of the 3-way ping allows for extra chances
to determine packet loss more efficiently. Also, with 3-way ping
disabled, the listener will receive no client performance
indicators, nor will the listener be able to determine directional
packet loss that it detects.
--no-match-packet-size
When sending replies, 2ping will try to match the packet size of
the received packet by adding padding if necessary, but will not
exceed --max-packet-size. --no-match-packet-size disabled this
behavior, always setting the minimum to --min-packet-size.
--no-send-version
Do not send the current running version of 2ping with each packet.
--notice=text
Arbitrary notice text to send with each packet. If the remote peer
supports it, this may be displayed to the user.
--packet-loss=out:in
Simulate random packet loss outbound and inbound. For example,
25:10 means a 25% chance of not sending a packet, and a 10% chance
of ignoring a received packet. A single number without colon
separation means use the same percentage for both outbound and
inbound.
--port=port
Use UDP port port. With --listen, this is the port to bind as,
otherwise this is the port to send to. Default is UDP port 15998.
--stats=interval
Print a line of brief current statistics every interval seconds.
The same line can be printed on demand by sending SIGQUIT to the
2ping process.
BUGS
There are probably lots and lots and lots of unknown bugs.
By default, source IP logic doesn't work as expected, see -I for
details. There appears to be no way to peg the source IP of reply UDP
packets to the destination of the packet that is being replied to. As
a result, packets always go out the interface's main IP address if not
specified manually. (Please, prove the author wrong.)
This manpage isn't finished yet, and may never be.
AUTHOR
2ping was written by Ryan Finnie <ryan@finnie.org>.
perl v5.20.2 2015-08-30 2PING(1)