Provided by: darkstat_3.0.719-1_amd64 bug


       darkstat - network statistics gatherer


       darkstat  [  -i  interface  ]  [  -r file ] [ --snaplen bytes ] [ --pppoe ] [ --syslog ] [
       --verbose ] [ --no-daemon ] [ --no-promisc ] [ --no-dns ] [ --no-macs ] [ --no-lastseen  ]
       [  -p  port  ]  [  -b  bindaddr  ]  [ --base path ] [ -f filter ] [ -l network/netmask ] [
       --local-only ] [ --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 ]


       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.


       -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

       --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.

              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!

              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.

              Produce more verbose debugging messages.

              Do not detach from the controlling terminal; stay in the foreground.

              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)

              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.

              Do not display MAC addresses in the hosts table.

              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

       --base path
              Specify the path of the base URL.  This can be useful if darkstat is accessed via a
              reverse proxy.

              For example, if you use Apache's mod_proxy and want to avoid  a  complicated  setup
              with  mod_proxy_html (and mod_header to unset the Accept-Encoding header), just set
              the base path to something like stats and use a config  similar  to  the  following

                      ProxyPass /stats/ http://localhost:667/stats/
                      ProxyPassReverse /stats/ http://localhost:667/stats/

              The default is / (i.e. the root).

       -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(8) 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.

              Make the web interface only display hosts on the "local network."  This is intended
              to be used together with the -l argument.

       --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

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

              The daylog format is:


              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

       --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

              And stop with:

                     kill `cat /var/run/darkstat/`

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

       --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.

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


       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

              darkstat -i fxp0 -b

       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

              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(8) manpage)

       We have a network consisting of a gateway server  (  and  a  few  workstations
       (,, 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

       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


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

       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.


   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.




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


       Emil Mikulic and others. (see the AUTHORS file)