tcpping.1.xml

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<manpage name='tcpping' section='1' desc='ping(8) written using TCP SYN probes'>

<synopsis>
	<cmd>tcpping 
	<arg>[-v]</arg>
	<arg>[-c count]</arg>
	<arg>[-p port]</arg>
	<arg>[-i interval]</arg>
	<arg>[-I interface]</arg>
	<arg>[-t ttl]</arg>
	<arg>[-S srcaddress]</arg>
	<arg>remote_host</arg>
	</cmd>
</synopsis>

<description>
<p><manref name='tcpping' section='1' /> is a utility designed to emulate
standard <manref name='ping' section='8' /> in nearly every meaningful way and
only diverge when necessary.  It sends out forged TCP SYN packets and listens
for a SYN/ACK, RST, or ICMP Time Exceeded message.  It counts and reports on
these results using an interface that is nearly identical to standard UNIX
ping.</p> 

<p><manref name='tcpping' section='1' /> works well in situations where ICMP
messages are either thought to be less responsive (through ICMP rate-limiting)
or filtered entirely via firewalls.</p>
</description>

<options>
	<option><p><opt>-v</opt></p>
	<optdesc>Display more verbose output</optdesc></option>

	<option><p><opt>-c COUNT</opt></p>
	<optdesc>Send COUNT packets and exit</optdesc></option>

	<option><p><opt>-p PORT</opt></p>
	<optdesc>Send packets to PORT instead of TCP port 80</optdesc></option>

	<option><p><opt>-i INTERVAL</opt></p>
	<optdesc>Wait INTERVAL seconds between packets (can be a decimal).  Defaults to 1s</optdesc></option>

	<option><p><opt>-I INTERFACE</opt></p>
	<optdesc>Send packets from, and probe for responses on, the given INTERFACE.  Defaults to the first external UP interface though it is not very robust.</optdesc></option>

	<option><p><opt>-t TTL</opt></p>
	<optdesc>Set TTL as the IP TTL for the probes.  Defaults to "sufficiently high"</optdesc></option>

	<option><p><opt>-S SRCADDRESS</opt></p>
	<optdesc>Set SRCADDRESS as the source address instead of the default IP of INTERFACE</optdesc></option>
</options>

<section name='Security'>
<p><manref name='tcpping' section='1' /> requires the CAP_NET_RAW capability
and is therefore installed as set-uid root.  Though numerous steps are taken to
ensure safety here (clearing the environment, safe input checks) there is
always some inherent risk.</p>

<p>It should also be noted that TCP SYN packets can overwhelm and crash some
servers as TCP SYN packets yielding a SYN/ACK will typically allocate resources
on the server.  Issuing this command with a very short interval to a server
listening on that port is effectively a SYN flood which the server may or may
not handle gracefully.</p>

<p>More information about SYN floods can be found here: <url
href='http://en.wikipedia.org/wiki/SYN_flood' /></p>
</section>

<section name='Author'>
<p>tcpping was originally written by Steven Kehlet &lt;steven@kehlet.cx&gt;.
It is now maintained by Jim Wyllie &lt;jwyllie83@gmail.com&gt; and has received
contributions from numerous individuals.  See LICENSE for details.</p>
</section>

<section name='Availability'>
<p>The canonical version of this code is available on github at <url
href='http://github.com/jwyllie83/tcpping' /></p>
</section>

<section name='Comments'>

<p>This man page was compiled from XML using <manref name='xmltoman'
section='1' />, found at <url href='http://masqmail.cx/xmltoman/' />.  You will
need that program to edit this manpage.</p>

</section>

</manpage>