/usr/share/ntop/html/ntop.html

<!-- Creator     : groff version 1.19.2 -->
<!-- CreationDate: Tue Jun  5 11:22:21 2012 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
       p     { margin-top: 0; margin-bottom: 0; }
       pre   { margin-top: 0; margin-bottom: 0; }
       table { margin-top: 0; margin-bottom: 0; }
</style>
<title>NTOP</title>

<!-- Added by insertssi -->
<link rel=stylesheet href="/style.css" type="text/css">
<!--#include virtual="/menuHead.html" -->
</head>
<body>
<!--#include virtual="/menuBody.html" -->

<h1 align=center>NTOP</h1>

<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#COMMAND&minus;LINE OPTIONS">COMMAND&minus;LINE OPTIONS</a><br>
<a href="#WEB VIEWS">WEB VIEWS</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<a href="#PRIVACY NOTICE">PRIVACY NOTICE</a><br>
<a href="#USER SUPPORT">USER SUPPORT</a><br>
<a href="#AUTHOR">AUTHOR</a><br>
<a href="#LICENCE">LICENCE</a><br>
<a href="#ACKNOWLEDGMENTS">ACKNOWLEDGMENTS</a><br>

<hr>


<a name="NAME"></a>
<h2>NAME</h2>


<p style="margin-left:11%; margin-top: 1em">ntop &minus;
display top network users</p>

<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>


<p style="margin-left:11%; margin-top: 1em"><b>ntop</b>
[<b>@filename</b>] [<b>-a</b>|<b>--access-log-file</b>
<i>&lt;path&gt;</i>] [<b>-b</b>|<b>--disable-decoders</b>]
[<b>-c</b>|<b>--sticky-hosts</b>]
[<b>-e</b>|<b>--max-table-rows</b>]
[<b>-f</b>|<b>--traffic-dump-file</b> <i>file&gt;</i>]
[<b>-g</b>|<b>--track-local-hosts</b>]
[<b>-h</b>|<b>--help</b>] [<b>-l</b>|<b>--pcap-log</b>
<i>&lt;path&gt;</i>] [<b>-m</b>|<b>--local-subnets</b>
<i>&lt;addresses&gt;</i>]
[<b>-n</b>|<b>--numeric-ip-addresses</b>]
[<b>-p</b>|<b>--protocols</b> <i>&lt;list&gt;</i>]
[<b>-q</b>|<b>--create-suspicious-packets</b>]
[<b>-r</b>|<b>--refresh-time</b> <i>&lt;number&gt;</i>]
[<b>-s</b>|<b>--no-promiscuous</b>]
[<b>-t</b>|<b>--trace-level</b> <i>&lt;number&gt;</i>]
[<b>-x</b> <i>&lt;max_num_hash_entries&gt;</i>]
[<b>-w</b>|<b>--http-server</b> <i>&lt;port&gt;</i>]
[<b>-z</b>|<b>--disable-sessions</b>]
[<b>-A</b>|<b>--set-admin-password</b> <i>password</i>]
[<b>-B</b>|<b>--filter-expression</b> <i>expression</i>]
[<b>-C</b> <i>&lt;config</i>mode&gt;<i>]</i>
[<b>-D</b>|<b>--domain</b> <i>&lt;name&gt;</i>]
[<b>-F</b>|<b>--flow-spec</b> <i>&lt;specs&gt;</i>]
[<b>-M</b>|<b>--no-interface-merge</b>]
[<b>-N</b>|<b>--wwn-map</b> <i>&lt;path&gt;</i>]
[<b>-O</b>|<b>----output-packet-path</b>
<i>&lt;path&gt;</i>] [<b>-P</b>|<b>--db-file-path</b>
<i>&lt;path&gt;</i>] [<b>-Q</b>|<b>--spool-file-path</b>
<i>&lt;path&gt;</i>] [<b>-U</b>|<b>--mapper</b>
<i>&lt;URL&gt;</i>] [<b>-V</b>|<b>--version]</b> [<b>-X</b>
<i>&lt;max_num_TCP_sessions&gt;</i>]
[<b>--disable-instantsessionpurge</b>]
[<b>--disable-mutexextrainfo</b>] [<b>--disable-ndpi</b>]
[<b>--disable-python</b>] [<b>--instance</b>]
[<b>--p3p-cp</b>] [<b>--p3p-uri</b>]
[<b>--skip-version-check=yes</b>] [<b>--w3c</b>]
[<b>-4</b>|<b>--ipv4]</b> [<b>-6</b>|<b>--ipv6]</b></p>

<p style="margin-left:11%; margin-top: 1em">Unix
options:</p>


<p style="margin-left:11%; margin-top: 1em">[<b>-d</b>|<b>--daemon</b>]
[<b>-i</b>|<b>--interface</b> <i>&lt;name&gt;</i>]
[<b>-u</b>|<b>--user</b> <i>&lt;user&gt;</i>]
[<b>-K</b>|<b>--enable-debug</b>] [<b>-L</b>]
[<b>--pcap_setnonblock</b>] [<b>--use-syslog=</b>
<i>&lt;facility&gt;</i>] [<b>--webserver-queue</b>
<i>&lt;number&gt;</i>]</p>

<p style="margin-left:11%; margin-top: 1em">Windows
option:</p>


<p style="margin-left:11%; margin-top: 1em">[<b>-i</b>|<b>--interface</b>
<i>&lt;number|name&gt;</i>]</p>

<p style="margin-left:11%; margin-top: 1em">OpenSSL
options:</p>


<p style="margin-left:11%; margin-top: 1em">[<b>-W</b>|<b>--https-server</b>
<i>&lt;port&gt;</i>] [<b>--ssl-watchdog</b>]</p>

<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>


<p style="margin-left:11%; margin-top: 1em"><b>ntop</b>
shows the current network usage. It displays a list of hosts
that are currently using the network and reports information
concerning the (IP and non-IP) traffic generated and
received by each host. <b>ntop</b> may operate as a
front-end collector (sFlow and/or netFlow plugins) or as a
stand-alone collector/display program. A web browser is
needed to access the information captured by the <b>ntop</b>
program.</p>

<p style="margin-left:11%; margin-top: 1em"><b>ntop</b> is
a hybrid layer 2 / layer 3 network monitor, that is by
default it uses the layer 2 Media Access Control (MAC)
addresses AND the layer 3 tcp/ip addresses. <b>ntop</b> is
capable of associating the two, so that ip and non-ip
traffic (e.g. arp, rarp) are combined for a complete picture
of network activity.</p>

<a name="COMMAND&minus;LINE OPTIONS"></a>
<h2>COMMAND&minus;LINE OPTIONS</h2>



<p style="margin-left:11%; margin-top: 1em"><b>@filename</b></p>

<p style="margin-left:12%;">The text of <b>filename</b> is
copied - ignoring line breaks and comment lines (anything
following a #) - into the command line. <b>ntop</b> behaves
as if all of the text had simply been typed directly on the
command line. For example, if the command line is &quot;-t 3
@d -u ntop&quot; and file d contains just the line
&rsquo;-d&rsquo;, then the effective command line is -t 3 -d
-u ntop. Multiple @s are permitted. Nested @s (an @ inside
the file) are not permitted.</p>

<p style="margin-left:12%; margin-top: 1em">Remember, most
<b>ntop</b> options are &quot;sticky&quot;, that is they
just set an internal flag. Invoking them multiple times
doesn&rsquo;t change <b>ntop&rsquo;s</b> behavior. However,
options that set a value, such as --trace-level, will use
the LAST value given: --trace-level 2 --trace-level 3 will
run as --trace-level 3.</p>

<p style="margin-left:12%; margin-top: 1em">Beginning with
3.1, many command-line options may also be set via the web
browser interface. These changes take effect on the next run
of and on each subsequent run until changed.</p>

<p style="margin-left:11%;"><b>-a |
--access-log-file</b></p>

<p style="margin-left:12%;">By default <b>ntop</b> does not
maintain a log of HTTP requests to the internal web server.
Use this parameter to request logging and to specify the
location of the file where these HTTP requests are
logged.</p>

<p style="margin-left:12%; margin-top: 1em">Each log entry
is in Apache-like style. The only difference between Apache
and <b>ntop</b> logs is that an additional column has been
added which has the time (in milliseconds) that <b>ntop</b>
needed to serve the request. Log entries look like this:</p>

<p style="margin-left:12%; margin-top: 1em">192.168.1.1 - -
[04/Sep/2003:20:38:55 -0500] - &quot;GET / HTTP/1.1&quot;
200 1489 4 <br>
192.168.1.1 - - [04/Sep/2003:20:38:55 -0500] - &quot;GET
/index_top.html HTTP/1.1&quot; 200 1854 4 <br>
192.168.1.1 - - [04/Sep/2003:20:38:55 -0500] - &quot;GET
/index_inner.html HTTP/1.1&quot; 200 1441 7 <br>
192.168.1.1 - - [04/Sep/2003:20:38:56 -0500] - &quot;GET
/index_left.html HTTP/1.1&quot; 200 1356 4 <br>
192.168.1.1 - - [04/Sep/2003:20:38:56 -0500] - &quot;GET
/home_.html HTTP/1.1&quot; 200 154/617 9 <br>
192.168.1.1 - - [04/Sep/2003:20:38:56 -0500] - &quot;GET
/home.html HTTP/1.1&quot; 200 1100/3195 10 <br>
192.168.1.1 - - [04/Sep/2003:20:38:56 -0500] - &quot;GET
/About.html HTTP/1.1&quot; 200 2010 10</p>

<p style="margin-left:12%; margin-top: 1em">This parameter
is the complete file name of the access log. In prior
releases it was erroneously called --access-log-path.</p>

<p style="margin-left:11%;"><b>-b |
--disable-decoders</b></p>

<p style="margin-left:12%;">This parameter disables
protocol decoders.</p>

<p style="margin-left:12%; margin-top: 1em">Protocol
decoders examine and collect information about layer 2
protocols such as NetBIOS or Netware SAP, as well as about
specific tcp/ip (layer 3) protocols, such as DNS, http and
ftp.</p>

<p style="margin-left:12%; margin-top: 1em">This support is
specifically coded for each protocol and is different from
the capability to count raw information (packets and bytes)
by protocol specified by the -p | --protocols parameter,
below.</p>

<p style="margin-left:12%; margin-top: 1em">Decoding
protocols is a significant consumer of resources. If the
<b>ntop</b> host is underpowered or monitoring a very busy
network, you may wish to disable protocol decoding via this
parameter. It may also be appropriate to use this parameter
if you believe that <b>ntop</b> has problems handling some
protocols that occur on your network.</p>

<p style="margin-left:12%; margin-top: 1em">Even if
decoding is disabled, ftp-data traffic is still decoded to
look for passive ftp port commands.</p>

<p style="margin-left:11%;"><b>-c | --sticky-hosts</b></p>

<p style="margin-left:12%;">Use this parameter to prevent
idle hosts from being purged from memory.</p>

<p style="margin-left:12%; margin-top: 1em">By default idle
hosts are periodically purged from memory. An idle host is
identified when no packets from or to that host have been
monitored for the period of time defined by the value of
PARM_HOST_PURGE_MINIMUM_IDLE in globals-defines.h.</p>

<p style="margin-left:12%; margin-top: 1em">If you use this
option, all hosts - active and idle - are retained in memory
for the duration of the <b>ntop</b> run.</p>

<p style="margin-left:12%; margin-top: 1em">P2P users, port
scans, popular web servers and other activity will cause
<b>ntop</b> to record data about a large number of hosts. On
an active network, this will consume a significant - and
always growing - amount of memory. It is strongly
recommended that you use a filtering expression to limit the
hosts which are stored if you use --sticky-hosts.</p>

<p style="margin-left:12%; margin-top: 1em">The idle purge
is a statistical one - a random selection of the eligible
hosts will be purged during each cycle. Thus it is possible
on a busy system for an idle host to remain in the
<b>ntop</b> tables and appear &rsquo;active&rsquo; for some
considerable time after it is truly idle.</p>

<p style="margin-left:11%;"><b>-d | --daemon</b></p>

<p style="margin-left:12%;">This parameter causes ntop to
become a daemon, i.e. a task which runs in the background
without connection to a specific terminal. To use
<b>ntop</b> other than as a casual monitoring tool, you
probably will want to use this option.</p>


<p style="margin-left:12%; margin-top: 1em"><b>WARNING:</b>
If you are running as a daemon, the messages from
<b>ntop</b> will be &rsquo;printed&rsquo; on to stdout and
thus dropped. You probably don&rsquo;t want to do this. So
remember to also use the -L or --use-syslog options to save
the messages into the system log.</p>

<p style="margin-left:11%;"><b>-e |
--max-table-rows</b></p>

<p style="margin-left:12%;">This defines the maximum number
of lines that <b>ntop</b> will display on each generated
ML page. If there are more lines to be displayed than this
setting permits, only part of the data will be displayed.
There will be page forward/back arrows placed at the bottom
of the page for navigation between pages.</p>

<p style="margin-left:11%;"><b>-f |
--traffic-dump-file</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b>
captures traffic from network interface cards (NICs) or from
netFlow/sFlow probes. However, <b>ntop</b> can also read
data from a file - typically a tcpdump capture or the output
from one of the <b>ntop</b> packet capture options.</p>

<p style="margin-left:12%; margin-top: 1em">if you specify
-f, <b>ntop</b> will not capture any traffic from NICs
during or after the file has been read. netFlow/sFlow
capture - if enabled - would still be active.</p>

<p style="margin-left:12%; margin-top: 1em">This option is
mostly used for debug purposes.</p>

<p style="margin-left:11%;"><b>-g |
--track-local-hosts</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b> tracks
all hosts that it sees from packets captured on the various
NICs. Use this parameter to tell <b>ntop</b> to capture data
only about local hosts. Local hosts are defined based on the
addresses of the NICs and those networks identified as local
via the -m | --local-subnets parameter.</p>

<p style="margin-left:12%; margin-top: 1em">This parameter
is useful on large networks or those that see many hosts,
(e.g. a border router or gateway), where information about
remote hosts is not desired/required to be tracked.</p>

<p style="margin-left:11%;"><b>-h | --help</b></p>

<p style="margin-left:12%;">Print help information for
<b>ntop,</b> including usage and parameters.</p>

<p style="margin-left:11%;"><b>-i | --interface</b></p>

<p style="margin-left:12%;">Specifies the network interface
or interfaces to be used by <b>ntop</b> for network
monitoring.</p>

<p style="margin-left:12%; margin-top: 1em">If multiple
interfaces are used (this feature is available only if ntop
is compiled with thread support) their names must be
separated with a comma. For instance -i
&quot;eth0,lo&quot;.</p>

<p style="margin-left:12%; margin-top: 1em">If not
specified, the default is the first Ethernet device, e.g.
eth0. The specific device that is &rsquo;first&rsquo; is
highly system dependent. Especially on systems where the
device name reflects the driver name instead of the type of
interface.</p>

<p style="margin-left:12%; margin-top: 1em">By default,
traffic information obtained by all the interfaces is merged
together as if the traffic was seen by only one interface.
Use the -M parameter to keep traffic separate by
interface.</p>

<p style="margin-left:12%; margin-top: 1em">If you do not
want <b>ntop</b> to monitor any interfaces, use -i none.</p>

<p style="margin-left:12%; margin-top: 1em">Under Windows,
the parameter value is either the number of the interface or
its name, e.g. {6252C14C-44C9-49D9-BF59-B2DC18C7B811}. Run
<b>ntop</b> -h to see a list of interface name-number
mappings (at the end of the help information).</p>

<p style="margin-left:11%;"><b>-l | --pcap-log</b></p>

<p style="margin-left:12%;">This parameter causes a dump
file to be created of the network traffic captured by
<b>ntop</b> in tcpdump (pcap) format. This file is useful
for debug, and may be read back into <b>ntop</b> by the -f |
--traffic-dump-file parameter. The dump is made after
processing any filter expression ( never even sees filtered
packets).</p>

<p style="margin-left:12%; margin-top: 1em">The output file
will be named
<i>&lt;path&gt;/&lt;log&gt;.&lt;device&gt;.pcap</i>
(Windows: <i>&lt;path&gt;/&lt;log&gt;.pcap</i> ), where
&lt;path&gt; is defined by the -O | --output-packet-path
parameter and &lt;log&gt; is defined by this -l | --pcap-log
parameter.</p>

<p style="margin-left:11%;"><b>-m | --local-subnets</b></p>

<p style="margin-left:12%;"><b>ntop</b> determines the ip
addresses and netmasks for each active interface. Any
traffic on those networks is considered local. This
parameter allows the user to define additional networks and
subnetworks whose traffic is also considered local in
<b>ntop</b> reports. All other hosts are considered
remote.</p>

<p style="margin-left:12%; margin-top: 1em">Commas separate
multiple network values. Both netmask and CIDR notation may
be used, even mixed together, for instance
&quot;131.114.21.0/24,10.0.0.0/255.0.0.0&quot;.</p>

<p style="margin-left:12%; margin-top: 1em">The local
subnet - as defined by the interface address(es) - is/are
always local and do not need to be specified. If you do give
the same value as a NIC&rsquo;s local address, a harmless
warning message is issued.</p>

<p style="margin-left:11%;"><b>-n |
--numeric-ip-addresses</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b>
resolves IP addresses using a combination of active
(explicit) DNS queries and passive sniffing. Sniffing of DNS
responses occurs when <b>ntop</b> receives a network packet
containing the response to some other user&rsquo;s DNS
query. <b>ntop</b> captures this information and enters it
into <b>ntop&rsquo;s</b> DNS cache, in expectation of
shortly seeing traffic addressed to that host. This way
<b>ntop</b> significantly reduces the number of DNS queries
it makes.</p>

<p style="margin-left:12%; margin-top: 1em">This parameter
causes <b>ntop</b> to skip DNS resolution, showing only
numeric IP addresses instead of the symbolic names. This
option can useful when the DNS is not present or quite
slow.</p>

<p style="margin-left:11%;"><b>-p | --protocols</b></p>

<p style="margin-left:12%;">This parameter is used to
specify the TCP/UDP protocols that <b>ntop</b> will monitor.
The format is &lt;label&gt;=&lt;protocol list&gt; [,
&lt;label&gt;=&lt;protocol list&gt;], where label is used to
symbolically identify the &lt;protocol list&gt;. The format
of &lt;protocol list&gt; is
&lt;protocol&gt;[|&lt;protocol&gt;], where &lt;protocol&gt;
is either a valid protocol specified inside the
/etc/services file or a numeric port range (e.g. 80, or
6000-6500).</p>

<p style="margin-left:12%; margin-top: 1em">A simple
example is
--protocols=&quot;HTTP=http|www|https|3128,FTP=ftp|ftp-data&quot;,
which reduces the protocols displayed on the &quot;IP&quot;
pages to three:</p>

<p style="margin-left:12%; margin-top: 1em">Host Domain
Data HTTP FTP Other IP <br>
ns2.attbi.com &lt;flag&gt; 954 63.9 % 0 0 954 <br>
64.124.83.112.akamai.com &lt;flag&gt; 240 16.1 % 240 0 0
<br>
64.124.83.99.akamai.com &lt;flag&gt; 240 16.1 % 240 0 0 <br>
toolbarqueries.google.com &lt;flag&gt; 60 4.0 % 60 0 0</p>

<p style="margin-left:12%; margin-top: 1em">If the
&lt;protocol list&gt; is very long you may store it in a
file (for instance protocol.list). To do so, specify the
file name instead of the &lt;protocol list&gt; on the
command line. e.g. <b>ntop -p protocol.list</b></p>

<p style="margin-left:12%; margin-top: 1em">If the -p
parameter is omitted the following default value is
used:</p>


<p style="margin-left:12%; margin-top: 1em">FTP=ftp|ftp-data
<br>
TP=http|www|https|3128 3128 is Squid, the HTTP cache <br>
DNS=name|domain <br>
Telnet=telnet|login <br>
NBios-IP=netbios-ns|netbios-dgm|netbios-ssn <br>
Mail=pop-2|pop-3|pop3|kpop|smtp|imap|imap2 <br>
DHCP-BOOTP=67-68 <br>
SNMP=snmp|snmp-trap <br>
NNTP=nntp <br>
NFS=mount|pcnfs|bwnfs|nfsd|nfsd-status <br>
X11=6000-6010 <br>
SSH=22</p>

<p style="margin-left:12%; margin-top: 1em">Peer-to-Peer
Protocols <br>
---------------------- <br>
Gnutella=6346|6347|6348 <br>
Kazaa=1214 <br>
WinMX=6699|7730 <br>
DirectConnect=0 Dummy port as this is a pure P2P protocol
<br>
eDonkey=4661-4665</p>

<p style="margin-left:12%; margin-top: 1em">Instant
Messenger <br>
----------------- <br>
Messenger=1863|5000|5001|5190-5193</p>

<p style="margin-left:12%; margin-top: 1em">NOTE: To
resolve protocol names to port numbers, they must be
specified in the system file used to list tcp/udp protocols
and ports, which is typically /etc/services file. You will
have to match the names in that file, exactly. Missing or
unspecified (non-standard) ports must be specified by
number, such as 3128 in our examples above.</p>

<p style="margin-left:12%; margin-top: 1em">If you have a
file named /etc/protocols, don&rsquo;t get confused by it,
as that&rsquo;s the Ethernet protocol numbers, which are not
what you&rsquo;re looking for.</p>

<p style="margin-left:11%;"><b>-q |
--create-suspicious-packets</b></p>

<p style="margin-left:12%;">This parameter tells
<b>ntop</b> to create a dump file of suspicious packets.</p>

<p style="margin-left:12%; margin-top: 1em">There are many,
many, things that cause a packet to be labeled as
&rsquo;suspicious&rsquo;, including:</p>

<p style="margin-left:12%; margin-top: 1em">Detected ICMP
fragment <br>
Detected Land Attack against host <br>
Detected overlapping/tiny packet fragment <br>
Detected traffic on a diagnostic port <br>
Host performed ACK/FIN/NULL scan <br>
Host rejected TCP session <br>
TP/FTP/SMTP/SSH detected at wrong port <br>
Malformed TCP/UDP/ICMP packet (packet too short) <br>
Packet # %u too long <br>
Received a ICMP protocol Unreachable from host <br>
Sent ICMP Administratively Prohibited packet to host <br>
Smurf packet detected for host <br>
TCP connection with no data exchanged <br>
TCP session reset without completing 3-way handshake <br>
Two MAC addresses found for the same IP address <br>
UDP data to a closed port <br>
Unknown protocol (no HTTP/FTP/SMTP/SSH) detected (on port
80/21/25/22) <br>
Unusual ICMP options</p>

<p style="margin-left:12%; margin-top: 1em">When this
parameter is used, one file is created for each network
interface where suspicious packets are found. The file is in
tcpdump (pcap) format and is named
&lt;path&gt;/ntop-suspicious-pkts.&lt;device&gt;.pcap, where
&lt;path&gt; is defined by the -O | --output-packet-path
parameter.</p>

<p style="margin-left:11%;"><b>-r | --refresh-time</b></p>

<p style="margin-left:12%;">Specifies the delay (in
seconds) between automatic screen updates for those
generated HTML pages which support them. This parameter
allows you to leave your browser window open and have it
always displaying nearly real-time data from
<b>ntop.</b></p>

<p style="margin-left:12%; margin-top: 1em">The default is
3 seconds. Please note that if the delay is very short (1
second for instance), <b>ntop</b> might not be able to
process all of the network traffic.</p>

<p style="margin-left:11%;"><b>-s |
--no-promiscuous</b></p>

<p style="margin-left:12%;">Use this parameter to prevent
from setting the interface(s) into promiscuous mode.</p>

<p style="margin-left:12%; margin-top: 1em">An interface in
promiscuous mode will accept ALL Ethernet frames, regardless
of whether they directed (addressed) to the specific network
interface (NIC) or not. This is an essential part of
enabling <b>ntop</b> to monitor an entire network. (Without
promiscuous mode, <b>ntop</b> will only see traffic directed
to the specific host it is running on, plus broadcast
traffic such as the arp and dhcp protocols.</p>

<p style="margin-left:12%; margin-top: 1em">Even if you use
this parameter, the interface could well be in promiscuous
mode if another application enabled it.</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop</b>
passes this setting on to libpcap, the packet capture
library. On many systems, a non-promiscuous open of the
network interface will fail, since the libpcap function on
most systems require it to capture raw packets ( <b>ntop</b>
captures raw packets so that we may view and analyze the
layer 2 - MAC - information).</p>

<p style="margin-left:12%; margin-top: 1em">Thus on most
systems, <b>ntop</b> must probably still be started as root,
and this option is largely ornamental. If it fails, you will
see a ***FATALERROR*** message referring to pcap_open_live()
and then an information message, &quot;Sorry, but on this
system, even with -s, it appears that ntop must be started
as root&quot;.</p>

<p style="margin-left:11%;"><b>-t | --trace-level</b></p>

<p style="margin-left:12%;">This parameter specifies the
&rsquo;information&rsquo; level of messages that you wish
<b>ntop</b> to display (on stdout or to the log). The higher
the trace level number the more information that is
displayed. The trace level ranges between 0 (no trace) and 5
(full debug tracings).</p>

<p style="margin-left:12%; margin-top: 1em">The default
trace value is 3.</p>

<p style="margin-left:12%; margin-top: 1em">Trace level 0
is not quite zero messages. Fatal errors and certain
startup/shutdown messages are always displayed. Trace level
1 is used to display errors only, level 2 for both errors
and warnings, and level 3 displays error, warning and
informational messages.</p>

<p style="margin-left:12%; margin-top: 1em">Trace level 4
is called &rsquo;noisy&rsquo; and it is - generating many
messages about the internal functioning of <b>ntop.</b>
Trace level 5 and above are &rsquo;noisy&rsquo; plus extra
logs, i.e. all possible messages, with a file:line tag
prepended to every message.</p>

<p style="margin-left:11%;"><b>-u | --user</b></p>

<p style="margin-left:12%;">Specifies the user <b>ntop</b>
should run as after it initializes.</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop</b>
must normally be started as root so that it has sufficient
privileges to open the network interfaces in promiscuous
mode and to receive raw frames. See the discussion of -s |
--no-promiscuous above, if you wish to try starting
<b>ntop</b> as a non-root user.</p>

<p style="margin-left:12%; margin-top: 1em">Shortly after
starting up, <b>ntop</b> becomes the user you specify here,
which normally has substantially reduced privileges, such as
no login shell. This is the userid which owns
<b>ntop&rsquo;s</b> database and output files.</p>

<p style="margin-left:12%; margin-top: 1em">The value
specified may be either a username or a numeric user id. The
group id used will be the primary group of the user
specified.</p>

<p style="margin-left:12%; margin-top: 1em">If this
parameter is not specified, ntop will try to switch first to
&rsquo;nobody&rsquo; and then to &rsquo;anonymous&rsquo;
before giving up.</p>

<p style="margin-left:12%; margin-top: 1em">NOTE: This
should not be root unless you really understand the security
risks. In order to prevent this by accident, the only way to
run <b>ntop</b> as root is to explicitly specify -u root.
<b>Don&rsquo;t do it.</b></p>

<p style="margin-left:11%;"><b>-x <br>
-X</b></p>

<p style="margin-left:12%;"><b>ntop</b> creates a new
hash/list entry for each new host/TCP session seen. In case
of DOS (Denial Of Service) an attacker can easily exhaust
all the host available memory because ntop is creating
entries for dummy hosts. In order to avoid this you can set
an upper limit in order to limit the memory ntop can
use.</p>

<p style="margin-left:11%;"><b>-w | --http-server <br>
-W | --https-server</b></p>

<p style="margin-left:12%;"><b>ntop</b> offers an embedded
web server to present the information that has been so
painstakingly gathered. An external HTTP server is NOT
required NOR supported. The <b>ntop</b> web server is
embedded into the application. These parameters specify the
port (and optionally the address (i.e. interface)) of the
<b>ntop</b> web server.</p>

<p style="margin-left:12%; margin-top: 1em">For example, if
started with -w 3000 (the default port), the URL to access
<b>ntop</b> is http://hostname:3000/. If started with a full
specification, e.g. -w 192.168.1.1:3000, <b>ntop</b> listens
on only that address/port combination.</p>

<p style="margin-left:12%; margin-top: 1em">If -w is set to
0 the web server will not listen for http://
connections.</p>

<p style="margin-left:12%; margin-top: 1em">-W operates
similarly, but controls the port for the https://
connections.</p>

<p style="margin-left:12%; margin-top: 1em">Some
examples:</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop -w 3000
-W 0</b> (this is the default setting) HTTP requests on port
3000 and no HTTPS.</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop -w 80
-W 443</b> Both HTTP and HTTPS have been enabled on their
most common ports.</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop -w 0 -W
443</b> HTTP disabled, HTTPS enabled on the common port.</p>

<p style="margin-left:12%; margin-top: 1em">Certain
sensitive, configuration pages of the <b>ntop</b> web server
are protected by a userid/password. By default, these are
the user/URL administration, filter, shutdown and reset
stats are password protected <br>
and are accessible initially only to user <b>admin</b> with
a password set during the first run of <b>ntop.</b></p>

<p style="margin-left:12%; margin-top: 1em">Users can
modify/add/delete users/URLs using ntop itself - see the
Admin tab.</p>

<p style="margin-left:12%; margin-top: 1em">The passwords,
userids and URLs to protect with passwords are stored in a
database file. Passwords are stored in an encrypted form in
the database for further security. Best practices call for
securing that database so that only the <b>ntop</b> user can
read it.</p>

<p style="margin-left:12%; margin-top: 1em">There is a
discussion in docs/FAQ about further securing the
<b>ntop</b> environment.</p>

<p style="margin-left:11%;"><b>-z |
--disable-sessions</b></p>

<p style="margin-left:12%;">This parameter disables TCP
session tracking. Use it for better performance or when you
don&rsquo;t really need/care to track sessions.</p>

<p style="margin-left:11%;"><b>-A |
--set-admin-password</b></p>

<p style="margin-left:12%;">This parameter is used to start
<b>ntop</b> , set the admin password and quit. It is quite
useful for installers that need to automatically set the
password for the admin user.</p>

<p style="margin-left:12%; margin-top: 1em">-A and
--set-admin-password (without a value) will prompt the user
for the password.</p>

<p style="margin-left:12%; margin-top: 1em">You may also
use this parameter to set a specific value using
--set-admin-password=value. <b>The = is REQUIRED and no
spaces are permitted!</b></p>

<p style="margin-left:12%; margin-top: 1em">If you attempt
to run <b>ntop</b> as a daemon without setting a password, a
FATAL ERROR message is generated and <b>ntop</b> stops.</p>

<p style="margin-left:11%;"><b>-B |
--filter-expression</b></p>

<p style="margin-left:12%;">Filters allows the user to
restrict the traffic seen by <b>ntop</b> on just about any
imaginable item.</p>

<p style="margin-left:12%; margin-top: 1em">The filter
expression is set at run time by this parameter, but it may
be changed during the <b>ntop</b> run on the Admin | Change
Filter web page.</p>

<p style="margin-left:12%; margin-top: 1em">The basic
format is <b>-B filter</b> , where the quotes are
<b>REQUIRED</b></p>

<p style="margin-left:12%; margin-top: 1em">The syntax of
the filter expression uses the same BPF (Berkeley Packet
Filter) expressions used by other packages such as
tcpdump</p>

<p style="margin-left:12%; margin-top: 1em">For instance,
suppose you are interested only in the traffic
generated/received by the host jake.unipi.it. <b>ntop</b>
can then be started with the following filter:</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop -B src
host jake.unipi.it or dst host jake.unipi.it</b></p>

<p style="margin-left:12%; margin-top: 1em">or in
shorthand:</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop -B host
jake.unipi.it or host jake.unipi.it</b></p>

<p style="margin-left:12%; margin-top: 1em">See the
&rsquo;expression&rsquo; section of the <b>tcpdump</b> man
page - usually available at
http://www.tcpdump.org/tcpdump_man.html - for further
information and the best quick guide to BPF filters
currently available.</p>

<p style="margin-left:12%; margin-top: 1em">WARNING: If you
are using complex filter expressions, especially those with
=s or meaningful spaces in them, be sure and use the long
option format, --filter-expression=&quot;xxxx&quot; and not
-B &quot;xxxx&quot;.</p>

<p style="margin-left:11%;"><b>-C |</b></p>

<p style="margin-left:12%;">This instruments ntop to be
used in two configurations: host and network mode. In host
mode (default) ntop works as usual: the IP addresses
received are those of real hosts. In host mode the IP
addresses received are those of the C-class network to which
the address belongs. Using ntop in network mode is extremely
useful when installed in a traffic exchange (e.g. in the
middle of the Internet) whereas the host mode should be used
when ntop is installed on the edge of a network (e.g. inside
a company). The network mode significantly reduces the
amount of work ntop has to perform and it has to be used
whenever ntop is used to find out how the network traffic
flows and not to pin-point specific hosts.</p>

<p style="margin-left:11%;"><b>-D | --domain</b></p>

<p style="margin-left:12%;">This identifies the local
domain suffix, e.g. ntop.org. It may be necessary, if
<b>ntop</b> is having difficulty determining it from the
interface.</p>

<p style="margin-left:11%;"><b>-F | --flow-spec</b></p>

<p style="margin-left:12%;">It is used to specify network
flows similar to more powerful applications such as
NeTraMet. A flow is a stream of captured packets that match
a specified rule. The format is</p>


<p style="margin-left:12%; margin-top: 1em"><b>&lt;flow-label&gt;=&rsquo;&lt;matching
expression&gt;&rsquo;[,&lt;flow-label&gt;=&rsquo;&lt;matching
expression&gt;&rsquo;]</b></p>

<p style="margin-left:12%; margin-top: 1em">, where the
label is used to symbolically identify the flow specified by
the expression. The expression is a bpf (Berkeley Packet
Filter) expression. If an expression is specified, then the
information concerning flows can be accessed following the
ML link named &rsquo;List NetFlows&rsquo;.</p>

<p style="margin-left:12%; margin-top: 1em">For instance
define two flows with the following expression
<b>LucaHosts=&rsquo;host jake.unipi.it or host
pisanino.unipi.it&rsquo;,GatewayRoutedPkts=&rsquo;gateway
gateway.unipi.it&rsquo; .</b></p>

<p style="margin-left:12%; margin-top: 1em">All the traffic
sent/received by hosts jake.unipi.it or pisanino.unipi.it is
collected by <b>ntop</b> and added to the LucaHosts flow,
whereas all the packet routed by the gateway
gateway.unipi.it are added to the GatewayRoutedPkts flow. If
the flows list is very long you may store in a file (for
instance flows.list) and specify the file name instead of
the actual flows list (in the above example, this would be
&rsquo;ntop -F flows.list&rsquo;).</p>

<p style="margin-left:12%; margin-top: 1em">Note that the
double quotations around the entire flow expression are
required.</p>

<p style="margin-left:11%;"><b>-K | --enable-debug</b></p>

<p style="margin-left:12%;">Use this parameter to simplify
application debug. It does three things: 1. Does not fork()
on the &quot;read only&quot; html pages. 2. Displays mutex
values on the configuration (info.html) page. 3. (If
available - glibc/gcc) Activates an automated backtrace on
application errors.</p>

<p style="margin-left:11%;"><b>-L |
--use-syslog=facility</b></p>

<p style="margin-left:12%;">Use this parameter to send log
messages to the system log instead of stdout.</p>

<p style="margin-left:12%; margin-top: 1em">-L and the
simple form --use-syslog use the default log facility,
defined as LOG_DAEMON in the #define symbol
DEFAULT_SYSLOG_FACILITY in globals-defines.h.</p>

<p style="margin-left:12%; margin-top: 1em">The complex
form, --use-syslog=facility will set the log facility to
whatever value (e.g. local3, security) you specify. <b>The =
is REQUIRED and no spaces are allowed!</b></p>

<p style="margin-left:12%; margin-top: 1em">This setting
applies both to <b>ntop</b> and to any child fork()ed for
reporting. If this parameter is not specified, any fork()ed
child will use the default value and will log it&rsquo;s
messages to the system log (this occurs because the fork()ed
child must give up it&rsquo;s access to the parents
stdout).</p>

<p style="margin-left:12%; margin-top: 1em">Because various
systems do not make the permissible names available, we have
a table at the end of globals-core.c. Look for
myFacilityNames.</p>

<p style="margin-left:11%;"><b>-M |
--no-interface-merge</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b> merges
the data collected from all of the interfaces (NICs) it is
monitoring into a single set of counters.</p>

<p style="margin-left:12%; margin-top: 1em">If you have a
simple network, say a small LAN with a connection to the
internet, merging data is good as it gives you a better
picture of the whole network. For larger, more complex
networks, this may not be desirable. You may also have other
reasons for wishing to monitor each interface separately,
for example DMZ vs. LAN traffic.</p>

<p style="margin-left:12%; margin-top: 1em">This option
instructs <b>ntop</b> not to merge network interfaces
together. This means that <b>ntop</b> will collect
statistics for each interface and report them
separately.</p>

<p style="margin-left:12%; margin-top: 1em">Only ONE
interface may be reported on at a time - use the <b>Admin |
Switch NIC</b> option on the web server to select which
interface to report upon.</p>

<p style="margin-left:12%; margin-top: 1em">Note that
activating either the netFlow and/or sFlow plugins will
force the setting of -M. Once enabled, you cannot go
back.</p>

<p style="margin-left:11%;"><b>-N | --wwn-map</b></p>

<p style="margin-left:12%;">This options names the file
providing the map of WWN to FCID/VSAN ids.</p>

<p style="margin-left:11%;"><b>-O |
--output-packet-path</b></p>

<p style="margin-left:12%;">This parameter defines the base
path for the ntop-suspicious-pkts.XXX.pcap and normal packet
dump files.</p>

<p style="margin-left:12%; margin-top: 1em">If this
parameter is not specified, the default value is the
config.h parameter CFG_DBFILE_DIR, which is set during
./configure from the --localstatedir= parameter. If
--localstatedir is not specified, it defaults to the
--prefix value plus /var (e.g. /usr/local/var).</p>

<p style="margin-left:12%; margin-top: 1em">Be aware that
this may not be what you expect when running <b>ntop</b> as
a daemon or Windows service. Setting an explicit and
absolute path value is <b>STRONGLY</b> recommended if you
use this facility.</p>

<p style="margin-left:11%;"><b>-P | --db-file-path <br>
-Q | --spool-file-path</b></p>

<p style="margin-left:12%;">These parameters specify where
<b>ntop</b> stores database files.</p>

<p style="margin-left:12%; margin-top: 1em">There are two
types, &rsquo;temporary&rsquo; - that is ones which need not
be retained from <b>ntop</b> run to <b>ntop</b> run, and
&rsquo;permanent&rsquo;, which must be retained (or
recreated).</p>

<p style="margin-left:12%; margin-top: 1em">The
&rsquo;permanent&rsquo; databases are the preferences,
&quot;prefsCache.db&quot; and the password file,
&quot;ntop_pw.db&quot;. These are stored in the -P |
--db-file-path specified location.</p>

<p style="margin-left:12%; margin-top: 1em">Certain plugins
use the -P | --db-file-path specified location for their
database (&quot;LsWatch.db&quot;) or (as a default value)
for files (.../rrd/...).</p>

<p style="margin-left:12%; margin-top: 1em">The
&rsquo;temporary&rsquo; databases are the address queue,
&quot;addressQueue.db&quot;, the cached DNS resolutions,
&quot;dnsCache.db&quot; and the MAC prefix (vendor table),
&quot;macPrefix.db&quot;.</p>

<p style="margin-left:12%; margin-top: 1em">If only -P |
--db-file-path is specified, it is used for both types of
databases.</p>

<p style="margin-left:12%; margin-top: 1em">The directories
named must allow read/write and file creation by the
<b>ntop</b> user. For security, nobody else should have even
read access to these files.</p>

<p style="margin-left:12%; margin-top: 1em">Note that the
default value is the config.h parameter CFG_DBFILE_DIR. This
is set during ./configure from the --localstatedir=
parameter. If --localstatedir is not specified, it defaults
to the --prefix value plus /var (e.g. /usr/local/var).</p>

<p style="margin-left:12%; margin-top: 1em">This may not be
what you expect when running <b>ntop</b> as a daemon or
Windows service.</p>

<p style="margin-left:12%; margin-top: 1em">Note that on
versions of <b>ntop</b> prior to 2.3, these parameters
defaulted to &quot;.&quot; (the current working directory,
e.g. the value returned by the pwd command) and caused havoc
as it was different when <b>ntop</b> was run from the
command line, vs. run via cron, vs. run from an
initialization script.</p>

<p style="margin-left:12%; margin-top: 1em">Setting an
explicit and absolute path value is <b>STRONGLY</b>
recommended.</p>

<p style="margin-left:11%;"><b>-U | --mapper</b></p>

<p style="margin-left:12%;">Specifies the URL of the
mapper.pl utility.</p>

<p style="margin-left:12%; margin-top: 1em">If provided,
<b>ntop</b> creates a clickable hyperlink on the &rsquo;Info
about host xxxxxx&rsquo; page to this URL by appending
?host=xxxxx. Any type of host lookup could be performed, but
this is intended to lookup the geographical location of the
host.</p>

<p style="margin-left:12%; margin-top: 1em">A cgi-based
mapper interface to http://www.multimap.com is part of the
<b>ntop</b> distribution [see www/Perl/mapper.pl]).</p>

<p style="margin-left:11%;"><b>-V | --version</b></p>

<p style="margin-left:12%;">Prints <b>ntop</b> version
information and then exits.</p>

<p style="margin-left:11%;"><b>-W | --https-server</b></p>

<p style="margin-left:12%;">(See the joint documentation
with the -w parameter, above)</p>


<p style="margin-left:11%;"><b>--disable-instantsessionpurge</b></p>

<p style="margin-left:12%;"><b>ntop</b> sets completed
sessions as &rsquo;timed out&rsquo; and then purge them
almost instantly, which is not the behavior you might expect
from the discussions about purge timeouts. This switch makes
ntop respect the timeouts for completed sessions. It is NOT
the default because a busy web server may have 100s or 1000s
of completed sessions and this would significantly increase
the amount of memory <b>ntop</b> uses.</p>


<p style="margin-left:11%;"><b>--disable-mutexextrainfo</b></p>

<p style="margin-left:12%;"><b>ntop</b> stores extra
information about the locks and unlocks of the protective
mutexes it uses. Since <b>ntop</b> uses fine-grained
locking, this information is updated frequently. On some
OSes, the system calls used to collect this informatio
(getpid() and gettimeofday()) are expensive. This option
disables the extra information. It should have no processing
impact on <b>ntop</b> <br>
- however should <b>ntop</b> actually deadlock, we would
lose the information that sometimes tells us why.</p>

<p style="margin-left:11%;"><b>--disable-ndpi</b></p>

<p style="margin-left:12%;"><b>ntop</b> is started without
nDPI support thus application protocols are not
recognized.</p>

<p style="margin-left:11%;"><b>--disable-python</b></p>

<p style="margin-left:12%;"><b>ntop</b> is started without
the Python interpreter. Beware as some ntop reports are
based on python, thus disabling it will prevent some reports
to work properly.</p>

<p style="margin-left:11%;"><b>--instance</b></p>

<p style="margin-left:12%; margin-top: 1em">You can run
multiple instances of <b>ntop</b> simultaneously by
specifying different -P values (typically through separate
ntop.conf files). If you set a value for this parameter
(available only on the command line), you (1) display the
&rsquo;instance&rsquo; name on every web page and (2) alter
the log prefix from &quot;NTOP&quot; to your chosen
value.</p>

<p style="margin-left:12%; margin-top: 1em">If you want to
make the tag more obvious, create a .instance class in
style.css, e.g.:</p>

<p style="margin-left:12%; margin-top: 1em">.instance {
<br>
color: #666666; <br>
font-size: 18pt; <br>
}</p>

<p style="margin-left:12%; margin-top: 1em">Note (UNIX): To
run completely different versions of the <b>ntop</b> binary,
you need to compile and install into a different library
(using ./configure --prefix) and then specify the
LD_LIBRARY_PATH before invoking, e.g.</p>


<p style="margin-left:12%; margin-top: 1em">LD_LIBRARY_PATH=/devel/lib/ntop/:...
/devel/bin/ntop ...args...</p>

<p style="margin-left:12%; margin-top: 1em">If present, a
file of the form &lt;instance&gt;_ntop_logo.gif will be used
instead of the normal ntop_logo.gif. This is tested for ONLY
once, at the beginning of the run. The EXACT word(s) of the
--instance flag are used, without testing if they make a
proper file name. If - for any reason - the file is not
found, an informational message is logged and the normal
logo file is used. To construct your own logo, make it a
300x40 transparent gif.</p>

<p style="margin-left:12%; margin-top: 1em">NOTE: On the
web pages, <b>ntop</b> uses the dladdr() function. The
original Solaris routine had a bug, replicated in FreeBSD
(and possibly other places) where it uses the ARGV[0] value
- which might be erroneous - instead of the actual file
name. If the &rsquo;running from&rsquo; value looks bogus
but the &rsquo;libaries in&rsquo; value looks ok, go with
the libarary.</p>

<p style="margin-left:11%;"><b>--p3p-cp <br>
--p3p-uri</b></p>

<p style="margin-left:12%; margin-top: 1em">P3P is a W3C
recommendation - http://www.w3.org/TR/P3P/ - for specifying
personal information a site collects and what it does with
the information. These parameters allow to return P3P
information. We do not supply samples.</p>

<p style="margin-left:11%;"><b>--pcap_setnonblock</b></p>

<p style="margin-left:12%;">On some platforms, the
<b>ntop</b> web server will hang or appear to hang (it
actually just responds incredibly slowly to the first
request from a browser session), while the rest of
<b>ntop</b> runs just fine. This is known to be an issue
under FreeBSD 4.x.</p>

<p style="margin-left:12%; margin-top: 1em">This option
sets the non-blocking option (assuming it&rsquo;s available
in the version of libpcap that is installed).</p>

<p style="margin-left:12%; margin-top: 1em">While this
works around the problem (by turing an interupt driven
process into a poll), it also MAY signifcantly increases the
cpu usage of <b>ntop.</b> Although it does not actually
interfere with other work, seeing <b>ntop</b> use 80-90% or
more of the cpu is not uncommon - don&rsquo;t say we
didn&rsquo;t warn you.</p>

<p style="margin-left:12%; margin-top: 1em"><b>THIS OPTION
IS OFFICIALLY UNSUPPORTED</b> and used at your own risk.
Read the docs/FAQ write-up.</p>


<p style="margin-left:11%;"><b>--skip-version-check=yes</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b>
accesses a remote file to periodically check if the most
current version is running. This option disables that check.
Please review the privacy notice at the bottom of this page
for more information. By default, the recheck period is
slightly more than 15 days. This can be adjusted via a
constant in globals-defines.h. If the result of the initial
check indicates that the <b>ntop</b> version is a &rsquo;new
development&rsquo; version (that is newer than the latest
published development version), the recheck is disabled.
This is because which fixes and enhancements were
present/absent from the code.</p>

<p style="margin-left:12%; margin-top: 1em">NOTE: At
present, the recheck does not work under Windows.</p>

<p style="margin-left:11%;"><b>--ssl-watchdog</b></p>

<p style="margin-left:12%; margin-top: 1em">Enable a
watchdog for webserver hangs. These usually happen when
connecting with older browsers. The user gets nothing back
and other users can&rsquo;t connect. Internally, packet
processing continues but there is no way to access the data
through the web server or shutdown ntop cleanly. With the
watchdog, a timeout occurs after 3 seconds, and processing
continues with a log message. Unfortunately, the user sees
nothing - it just looks like a failed connection. (also
available as a ./configure option, --enable-sslwatchdog)</p>

<p style="margin-left:11%;"><b>--w3c</b></p>

<p style="margin-left:12%;">By default, <b>ntop</b>
generates displayable but not great html. There are a number
of tags we do not generate because they cause problems with
older browsers which are still commonly used or are
important to look good on real-world browsers. This flag
tells <b>ntop</b> to generate &rsquo;BETTER&rsquo; (but not
perfect) w3c compliant html 4.01 output. This in no way
addresses all of the compatibility and markup issues. Over
time, we would like to make <b>ntop</b> more compatible, but
it will never be 100%. If you find any issues, please report
them to ntop-dev.</p>

<p style="margin-left:11%;"><b>-4 | --ipv4</b></p>

<p style="margin-left:12%;">Use IPv4 connections.</p>

<p style="margin-left:11%;"><b>-6 | --ipv6</b></p>

<p style="margin-left:12%;">Use IPv6 connections</p>

<a name="WEB VIEWS"></a>
<h2>WEB VIEWS</h2>


<p style="margin-left:11%; margin-top: 1em">While
<b>ntop</b> is running, multiple users can access the
traffic information using their web browsers. <b>ntop</b>
does not generate &rsquo;fancy&rsquo; or
&rsquo;complex&rsquo; html, although it does use frames,
shallowly nested tables and makes some use of JavaScript and
Cascading Style Sheets.</p>

<p style="margin-left:11%; margin-top: 1em">Beginning with
release 3.1, the menus are cascading dropdowns via
JSCookMenu. With release 3.2, this extends to plugins.</p>

<p style="margin-left:11%; margin-top: 1em">We do not
expect problems with any current web browser, but our
ability to test with less common ones is very limited.
Testing has included Firefox and Internet Explorer, with
very limited testing on other current common browsers such
as Opera.</p>

<p style="margin-left:11%; margin-top: 1em">In
documentation and this man page, when we refer to a page
such as Admin | Switch NIC, we mean the Broad category
&quot;Admin&quot; and the detailed item &quot;Switch
NIC&quot; on that Admin menu.</p>

<a name="NOTES"></a>
<h2>NOTES</h2>


<p style="margin-left:11%; margin-top: 1em"><b>ntop</b>
requires a number of external tools and libraries to
operate. Certain other tools are optional, but add to the
program&rsquo;s capabilities. <b><br>
--webserver-queue</b></p>

<p style="margin-left:12%;">Specifies the maximum number of
web server requests for the tcp/ip stack to retain in
it&rsquo;s queue awaiting delivery to the <b>ntop</b> web
server. Requests in excess of this queue may be dropped
(allowing for retransmission) or rejected at the tcp/ip
stack level, depending upon the OS. Whatever happens,
happens at the OS level, without any information being
delivered to <b>ntop</b></p>

<p style="margin-left:12%; margin-top: 1em">Required
libraries include:</p>

<p style="margin-left:12%; margin-top: 1em"><b>libpcap</b>
from http://www.tcpdump.org/, version 0.7.2 or newer. 0.8.3
or newer is strongly recommended.</p>

<p style="margin-left:12%; margin-top: 1em">The Windows
version makes use of <b>WinPcap</b> (libpcap for Windows)
which may be downloaded from
http://winpcap.polito.it/install/default.htm.</p>

<p style="margin-left:12%; margin-top: 1em">WARNING: The
2.x releases of <b>WinPcap</b> will NOT support SMP
machines.</p>

<p style="margin-left:12%; margin-top: 1em"><b>gdbm</b>
from http://www.gnu.org/software/gdbm/gdbm.html</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop</b>
requires a POSIX threads library. As of <b>ntop</b> 3.2, the
single-threaded version of <b>ntop</b> is no longer
available.</p>

<p style="margin-left:12%; margin-top: 1em">The <b>gd</b>
2.x library, for the creation of png files, available at
http://www.boutell.com/gd/.</p>

<p style="margin-left:12%; margin-top: 1em">The
<b>libpng</b> 1.2.x library, for the creation of png files,
available at http://www.libpng.org/pub/png/libpng.html.</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop</b>
should support both gd 1.X and libpng 1.0.x libraries but
this has not been tested. Note that there are
incompatibilities if you compile with one version of these
libraries and then run with the other. Please read the
discussion in docs/FAQ before reporting ANY problems of this
nature.</p>

<p style="margin-left:12%; margin-top: 1em">(if an https://
server is desired) <b>openSSL</b> from the OpenSSL project
available at http://www.openssl.org.</p>

<p style="margin-left:12%; margin-top: 1em">The
<b>rrdtool</b> library is required by the rrd plugin.
rrdtool creates &rsquo;Round-Robin databases&rsquo; which
are used to store and graph historical data in a format that
permits long duration retention without growing larger over
time. The rrdtool home page is
http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/</p>

<p style="margin-left:12%; margin-top: 1em"><b>ntop</b>
includes a limited version of rrdtool 1.0.49 in the myrrd/
directory. Users of <b>ntop</b> 3.2 should not need to
specifically install rrdtool.</p>

<p style="margin-left:12%; margin-top: 1em">The
<b>sflow</b> Plugin is courtesy of and supported by InMon
Corporation, http://www.inmon.com/sflowTools.htm.</p>

<p style="margin-left:12%; margin-top: 1em">There are other
optional libraries. See the output of ./configure for a
fuller listing.</p>

<p style="margin-left:12%; margin-top: 1em">Tool locations
are current as of August 2005 - please send email to report
new locations or dead links.</p>

<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>


<p style="margin-left:11%; margin-top: 1em"><b>top</b>(1),
<b>tcpdump</b>(8). <b>pcap</b>(3).</p>

<a name="PRIVACY NOTICE"></a>
<h2>PRIVACY NOTICE</h2>


<p style="margin-left:11%; margin-top: 1em">By default at
startup and at periodic intervals, the <b>ntop</b> program
will retrieve a file containing current ntop program version
information. Retrieving this file allows this <b>ntop</b>
instance to confirm that it is running the most current
version.</p>

<p style="margin-left:11%; margin-top: 1em">The retrieval
is done using standard http:// requests, which will create
log records on the hosting system. These log records do
contain information which identifies a specific <b>ntop</b>
site. Accordingly, you are being notified that this
individually identifiable information is being transmitted
and recorded.</p>

<p style="margin-left:11%; margin-top: 1em">You may request
- via the <b>--skip-version-check=yes</b> run-time option - that
this check be eliminated. If you use this option, no
individually identifiable information is transmitted or
recorded, because the entire retrieval and check is
skipped.</p>

<p style="margin-left:11%; margin-top: 1em">We ask you to
allow this retrieval and check, because it benefits both you
and the <b>ntop</b> developers. It benefits you because you
will be automatically notified if the <b>ntop</b> program
version is obsolete, becomes unsupported or is no longer
current. It benefits the developers of <b>ntop</b> because
it allows us to determine the number of active <b>ntop</b>
instances, and the operating system/versions that users are
running <b>ntop</b> under. This allows us to focus
development resources on systems like those our users are
using <b>ntop</b> on.</p>

<p style="margin-left:11%; margin-top: 1em">The
individually identifiable information is contained in the
web server log records which are automatically created each
time the version file is retrieved. This is a function of
the web server and not of <b>ntop</b> , but we do take
advantage of it. The log record shows the IP address of the
requestor (the <b>ntop</b> instance) and a User-Agent header
field. We place information in the User-Agent header as
follows:</p>


<p style="margin-left:11%; margin-top: 1em">ntop/&lt;version&gt;
<br>
host/&lt;name from config.guess&gt; <br>
distro/&lt;if one&gt; <br>
release/&lt;of the distro, also if one&gt; <br>
kernrlse/&lt;kernel version or release&gt; <br>
GCC/&lt;version&gt; <br>
config() &lt;condensed parameters from ./configure&gt; <br>
run() &lt;condensed flags - no data - from the execution
line&gt; <br>
libpcap/&lt;version&gt; <br>
gdbm/&lt;version&gt; <br>
openssl/&lt;version&gt; <br>
zlib/&lt;version&gt; <br>
access/&lt;http, https, both or none&gt; <br>
interfaces() &lt;given interface names&gt;</p>

<p style="margin-left:11%; margin-top: 1em">For
example:</p>

<p style="margin-left:11%; margin-top: 1em">ntop/2.2.98
host/i686-pc-linux-gnu distro/redhat release/9
kernrlse/2.4.20-8smp <br>
GCC/3.2.2 config(i18n) run(i; u; P; w; t; logextra; m;
instantsessionpurge; <br>
schedyield; d; usesyslog=; t) gdbm/1.8.0 openssl/0.9.7a
zlib/1.1.4 <br>
access/http interfaces(eth0,eth1)</p>

<p style="margin-left:11%; margin-top: 1em">Distro and
release information is determined at compile time and
consists of information typically found in the /etc/release
(or similar) file. See the <b>ntop</b> tool linuxrelease for
how this is determined.</p>

<p style="margin-left:11%; margin-top: 1em">gcc compiler
version (if available) is the internal version #s for the
gcc compiler, e.g. 3.2.3.</p>

<p style="margin-left:11%; margin-top: 1em">kernrlse is the
Linux Kernel version or the xBSD &rsquo;release&rsquo; such
as 4.9-RELEASE and is determined from the uname data (if
it&rsquo;s available).</p>

<p style="margin-left:11%; margin-top: 1em">The ./configure
parameters are stripped of directory paths, leading -s, etc.
to create a short form that shows us what ./configure
parameters people are using.</p>

<p style="margin-left:11%; margin-top: 1em">Similarly, the
run time parameters are stripped of data and paths, just
showing which flags are being used.</p>

<p style="margin-left:11%; margin-top: 1em">The libpcap,
gdbm, openssl and zlib versions come from the strings
returned by the various inquiry functions (if they&rsquo;re
availabe).</p>

<p style="margin-left:11%; margin-top: 1em">Here&rsquo;s a
sample log record:</p>

<p style="margin-left:11%; margin-top: 1em">67.xxx.xxx.xxx
- - [28/Dec/2003:12:11:46 -0500] &quot;GET /version.xml
TP/1.0&quot; <br>
200 1568 www.burtonstrauss.com &quot;-&quot;
&quot;ntop/2.2.98 host/i686-pc-linux-gnu <br>
distro/redhat release/9 kernrlse/2.4.20-8smp GCC/3.2.2
config(i18n) <br>
run(i; u; P; w; t; logextra; m; instantsessionpurge;
schedyield; d; <br>
usesyslog=) libpcap/0.8 gdbm/1.8.0 openssl/0.9.7a zlib/1.1.4
access/http <br>
interfaces(eth0,eth1,eth2)&quot; &quot;-&quot;</p>

<a name="USER SUPPORT"></a>
<h2>USER SUPPORT</h2>


<p style="margin-left:11%; margin-top: 1em">Please send bug
reports to the ntop-dev &lt;ntop-dev@ntop.org&gt; mailing
list. The ntop &lt;ntop@ntop.org&gt; mailing list is used
for discussing ntop usage issues. In order to post messages
on the lists a (free) subscription is required to
limit/avoid spam. Please do NOT contact the author directly
unless this is a personal question.</p>

<p style="margin-left:11%; margin-top: 1em">Commercial
support is available upon request. Please see the ntop site
for further info.</p>

<p style="margin-left:11%; margin-top: 1em">Please send
code patches to &lt;patch@ntop.org&gt;.</p>

<a name="AUTHOR"></a>
<h2>AUTHOR</h2>


<p style="margin-left:11%; margin-top: 1em">ntop&rsquo;s
author is Luca Deri (http://luca.ntop.org/) who can be
reached at &lt;deri@ntop.org&gt;.</p>

<a name="LICENCE"></a>
<h2>LICENCE</h2>


<p style="margin-left:11%; margin-top: 1em">ntop is
distributed under the GNU GPL licence
(http://www.gnu.org/).</p>

<a name="ACKNOWLEDGMENTS"></a>
<h2>ACKNOWLEDGMENTS</h2>


<p style="margin-left:11%; margin-top: 1em">The author
acknowledges the Centro Serra of the University of Pisa,
Italy (http://www-serra.unipi.it/) for hosting the ntop
sites (both web and mailing lists), and Burton Strauss
&lt;burton@ntopsupport.com&gt; for his help and user
assistance. Many thanks to Stefano Suin
&lt;stefano@ntop.org&gt; and Rocco Carbone
&lt;rocco@ntop.org&gt; for contributing to the project.</p>
<hr>
</body>
</html>
ntop-data 3:5.0.1+dfsg1-2.2ubuntu1 / usr / share / ntop / html / ntop.html
