Provided by: darkstat_3.0.714+dfsg-1_i386 bug

NAME

       darkstat - network statistics gatherer

SYNOPSIS

       darkstat [ -i interface ] [ -r file ] [ --snaplen bytes ] [ --pppoe ] [
       --syslog ] [ --verbose ] [ --no-daemon ] [ --no-promisc ] [ --no-dns  ]
       [ --no-macs ] [ --no-lastseen ] [ -p port ] [ -b bindaddr ] [ -f filter
       ] [ -l network/netmask ] [  --chroot  dir  ]  [  --user  username  ]  [
       --daylog  filename  ]  [  --import  filename  ] [ --export filename ] [
       --pidfile filename ] [ --hosts-max count ] [  --hosts-keep  count  ]  [
       --ports-max  count  ]  [ --ports-keep count ] [ --highest-port port ] [
       --wait secs ] [ --hexdump ]

DESCRIPTION

       darkstat is a packet sniffer that runs as a background process, gathers
       all sorts of statistics about network usage, and serves them over HTTP.

       All settings are passed on the commandline.

OPTIONS

       -i interface
              Capture traffic on the specified network interface.  This is the
              only mandatory commandline argument.

       -r file
              Instead of capturing  live  traffic,  read  it  from  a  pcap(3)
              capture   file.    This  is  only  useful  for  development  and
              benchmarking.  The -r and -i arguments are mutually exclusive.

       --snaplen bytes
              How many bytes to capture from the start of  each  packet.   You
              should  not  need  to  specify  this; darkstat will calculate it
              automatically.

       --pppoe
              Don't use this.

              Instead,  capture  on  the  tunnel  interface  that  your  PPPoE
              software  provides,  for  example  tun0  on  FreeBSD,  pppoe0 on
              OpenBSD or NetBSD.

              If you really must, you can capture on an Ethernet interface and
              pass  this  argument  to  have  darkstat decode PPPoE frames and
              ignore everything else.  Make sure you also specify  your  local
              address with the -l argument!

       --syslog
              Errors,  warnings,  and  verbose  messages  will  go  to  syslog
              (facility daemon, priority debug) instead of stderr.

              On some systems, these messages  end  up  in  /var/log/debug  by
              default.

       --verbose
              Produce more verbose debugging messages.

       --no-daemon
              Do  not  detach  from  the  controlling  terminal;  stay  in the
              foreground.

       --no-promisc
              Do not use promiscuous mode to capture.  Note that an  interface
              may   already  be  in  promiscuous  mode,  or  may  later  enter
              promiscuous  mode,  due  to  circumstances   beyond   darkstat's
              control.  If this is a problem, use -f to specify an appropriate
              bpf(4) filter.

       --no-dns
              Do not resolve IPs to host names.  This can significantly reduce
              memory footprint on small systems as an extra process is created
              for DNS resolution.

       --no-macs
              Do not display MAC addresses in the hosts table.

       --no-lastseen
              Do not display the last seen time in the hosts table.

       -p port
              Bind the web interface to the specified port.   The  default  is
              667.

       -b bindaddr
              Bind the web interface to the specified address.  The default is
              to listen on all interfaces.

       -f filter
              Use the specified filter expression when capturing traffic.  The
              filter  syntax  is  beyond the scope of this manual page; please
              refer to the tcpdump(1) documentation.

       -l network/netmask
              Define a "local network" according to the  network  and  netmask
              addresses.  All traffic entering or leaving this network will be
              graphed, as opposed to the default behaviour  of  only  graphing
              traffic to and from the local host.

              The  rule  is  that  if  ip_addr & netmask == network, then that
              address is considered local.  See the usage example below.

       --chroot dir
              Force  darkstat  to  chroot()  into  the  specified   directory.
              Without  this  argument, a default directory will be used, which
              is  determined   at   build   time.    Usually   /var/empty   or
              /var/lib/empty.

              For  security  reasons,  this directory should be empty, and the
              user that darkstat is running as should not have write access to
              it.

              However,  if you wish to use --daylog or --export, darkstat will
              need write access to the chroot.  If you are uncomfortable  with
              the  security  implications,  don't  use  any functionality that
              requires write access.

       --user username
              Force darkstat to drop privileges to the  uid  and  gid  of  the
              specified  user.  Without this argument, a default value will be
              used, which is set at build time.  Usually nobody.

              For security reasons, this should not be root.

       --daylog filename
              Log daily traffic statistics into the named  file,  relative  to
              the  chroot  directory.   If  you wish to use --daylog, you must
              first specify a --chroot directory, and it must be writeable  by
              the   darkstat   user.    A   writeable   chroot   has  security
              implications; if you are uncomfortable with this, do not use the
              --daylog functionality.

              If   the  daylog  argument  is  not  specified,  no  logging  is
              performed.

              The daylog format is:

              localtime|time_t|bytes_in|bytes_out|pkts_in|pkts_outs

              Lines starting with  a  #  are  comments  stating  when  logging
              started and stopped.

       --import filename
              Upon  starting,  import a darkstat database from the named file,
              relative to the chroot directory.  If you wish to use  --import,
              you  must  first specify a --chroot directory.  If the import is
              unsuccessful, darkstat will start with an empty database.

       --export filename
              On shutdown, or upon receiving SIGUSR1 or  SIGUSR2,  export  the
              in-memory  database  to  the  named file, relative to the chroot
              directory.  If you wish to use --export, you must first  specify
              a  --chroot  directory, and it must be writeable by the darkstat
              user.  A writeable chroot has security implications - if you are
              uncomfortable with this, do not use the --export functionality.

       --pidfile filename
              Creates a file containing the process ID of darkstat.  This file
              will be unlinked upon clean shutdown.  As with all pidfiles,  if
              darkstat dies uncleanly, a stale pidfile can be left over.

              For example, start darkstat with:

                     darkstat  -i  fxp0  --chroot  /var/run/darkstat --pidfile
                     darkstat.pid

              And stop with:

                     kill `cat /var/run/darkstat/darkstat.pid`

              By default, kill(1) will send SIGTERM, which will cause darkstat
              to shut down cleanly.

       --hosts-max count
              The  maximum  number  of  hosts  that  will be kept in the hosts
              table.  This is used to limit how much accounting data  will  be
              kept  in memory.  The number of --hosts-max must be greater than
              --hosts-keep

       --hosts-keep count
              When the hosts table hits --hosts-max and traffic is seen from a
              new  host,  we  clean  out the hosts table, keeping only the top
              --hosts-keep number of hosts, sorted by total traffic.

       --ports-max count
              The maximum number of ports that will be tracked for each  host.
              This  is  used to limit how much accounting data will be kept in
              memory.   The  number  of  --ports-max  must  be  greater   than
              --ports-keep

       --ports-keep count
              When  a  ports  table fills up, this many ports are kept and the
              rest are discarded.

       --highest-port port
              Ports that are numerically higher than this will not  appear  in
              the  per-host ports tables, although their traffic will still be
              accounted for.  This can be used to hide  ephemeral  ports.   By
              default, all ports are tracked.

       --wait secs
              Don't  use  this.  It's a hack to help victims of NetworkManager
              and similar systems.

              You should start darkstat after the capture interface  has  come
              up.   If  you  can't,  specifying  the  --wait  option will make
              darkstat sleep up to the specified number  of  seconds  for  the
              interface to become ready.  Zero means wait indefinitely.

       --hexdump
              Show hex dumps of received traffic.  This is only for debugging,
              and implies --verbose and --no-daemon.

USAGE EXAMPLES

       To gather statistics on the fxp0 interface:

              darkstat -i fxp0

       We want to account for traffic on the  Internet-facing  interface,  but
       only  serve web pages to our private local network where we have the IP
       address 192.168.0.1:

              darkstat -i fxp0 -b 192.168.0.1

       We want to serve web pages on the standard HTTP port:

              darkstat -i fxp0 -p 80

       We are on Optus (cable) and don't want to account for the constant  ARP
       traffic we are receiving:

              darkstat -i fxp0 -f "not arp"

       We only want to account for SSH traffic:

              darkstat -i fxp0 -f "port 22"

       We don't want to account for traffic between internal IPs:

              darkstat  -i  fxp0  -f  "not  (src  net  192.168.0  and  dst net
              192.168.0)"

       (For a full  reference  on  filter  syntax,  refer  to  the  tcpdump(1)
       manpage)

       We  have  a  network consisting of a gateway server (192.168.1.1) and a
       few workstations (192.168.1.2, 192.168.1.3, etc.) and we want to  graph
       all  traffic  entering  and  leaving  the  local  network, not just the
       gateway server (which is running darkstat):

              darkstat -i fxp0 -l 192.168.1.0/255.255.255.0

       On some systems, we can't capture on a "decoded" interface but only  on
       nas0  which returns PPPoE encapsulated packets.  Do PPPoE decoding, and
       override the  local  IP  manually  since  it  cannot  be  automatically
       detected.  Note the /32 netmask:

              darkstat -i nas0 --pppoe -l 192.168.1.1/255.255.255.255

SIGNALS

       To  shut  darkstat down cleanly, send a SIGTERM or SIGINT signal to the
       darkstat parent process.

       Sending the SIGUSR1 signal will cause darkstat to  empty  out  its  in-
       memory  database.   If an --export file was set, it will first save the
       database to file.  Sending  SIGUSR2  will  save  the  database  without
       emptying it.

FREQUENTLY ASKED QUESTIONS

   How many bytes does each bar on the graph represent?
       Hover  your mouse cursor over a bar and you should get a tooltip saying
       exactly how many bytes in and out the bar represents.

   Why aren't there labels / tics / a scale on the graphs?
       Because implementing them is hard.  And doing so correctly,  and  in  a
       way that works across all browsers, looks pretty much impossible.

       I  might attempt it some day.  In the meantime, patches would be gladly
       accepted.

   Why are the graphs blank? All the bars are zero.
       The graphs only show  traffic  in/out  of  the  local  host,  which  is
       determined  by  getting the IP address of the interface you're sniffing
       on.

       You can  use  the  -l  argument  to  override  the  local  address  for
       accounting  purposes.  You can also use it to do accounting for a whole
       subnet by specifying an appropriate netmask.

SEE ALSO

       tcpdump(1)

HISTORY

       darkstat was written  in  2001,  largely  as  a  result  of  a  certain
       Australian  cable  Internet  provider introducing a 3GB monthly traffic
       limit.

AUTHORS

       Emil Mikulic and others. (see the AUTHORS file)

WEBSITE

       http://unix4lyfe.org/darkstat/