Provided by: darkstat_3.0.714+dfsg-1_amd64 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/