Provided by: nfdump_1.6.17-1_amd64 bug


       nfcapd - netflow capture daemon


       nfcapd [options]


       nfcapd  is  the netflow capture daemon of the nfdump tools. It reads netflow data from the
       network and stores it into files. The output file is  automatically  rotated  and  renamed
       every  n  minutes - typically 5 min - according the timestamp YYYYMMddhhmm of the interval
       e.g.  nfcapd.201107110845 contains the data from July 11th 2011 08:45 onward.

       Netflow version v1, v5, v7 and v9 and IPFIX are transparently supported.

       Extensions: nfcapd supports a large number of v9 tags. In order to optimise disk space and
       performance,  v9  tags  are  grouped  into  a number of extensions which may or may not be
       stored into the data file. Therefore the v9 templates configured on the  exporter  may  be
       tuned  according  the  collector.  Only those tags common to both are stored into the data

       Sampling: By default, the sampling rate is set to 1 (unsampled)  or  to  any  given  value
       specified  by  the  -s  cmd  line  option. If sampling information is found in the netflow
       stream, it overwrites  the  default  value.  Sampling  is  automatically  recognised  when
       announced in v9 option templates (tags #34, #35 or #48, #49, #50 ) or in the unofficial v5
       header hack.  Note: Not all platforms (or IOS/JunOS versions) support  exporting  sampling
       information  in  netflow data, even if sampling is configured. The number of bytes/packets
       in each netflow record is automatically multiplied by the sampling rate.  The total number
       of  flows  is not changed as this is not accurate enough. (Small flows versus large flows)
       If the default sampling rate given by -s is negative, this will hard overwrite any  device
       specific announced sampling rates.

       NSEL/ASA  Support:  nfcapd  can  be  compiled with NSEL/ASA support included. See notes on

       NEL (NAT Event logging): nfcapd can be compiled with  CISCO  NEL  support  included.   See
       notes on NEL.


       -p portnum
          Specifies the port number to listen. Default port is 9995

       -b bindhost
          Specifies  the  hostname/IPv4/IPv6  address  to  bind  for listening. This can be an IP
          address or a hostname, resolving to an IP address attached to an  interface.   Defaults
          to any available IPv4 interface, if not specified.

       -4 Forces  nfcapd  to  listen  on  IPv4  addresses only. Can be used together with -b if a
          hostname has an IPv4 and IPv6 address record.

       -6 Forces nfcapd to listen on IPv6 addresses only. Can be  used  together  with  -b  if  a
          hostname has an IPv4 and IPv6 address record. Depending on the socket implementation -6
          also accepts IPv4 data.

       -J MulticastGroup
          Join the specified IPv4 or IPv6 multicast group for listening.

       -R host[/port}
          Enable packet repeater. Send all incoming packets to another host and  port.   host  is
          either  a  valid  IPv4/IPv6  address, or a valid symbolic hostname, which resolves to a
          IPv6 or IPv4 address. port may be omitted and defaults  to  port  9995.  Note:  Due  to
          IPv4/IPv6 accepted addresses the port separator is '/'.

       -I IdentString ( capital letter i )
          Specifies an ident string, which describes the source e.g. the name of the router. This
          string is put into the stat record to identify the source. Default is 'none'.  This  is
          for compatibility with nfdump 1.5.x and used to specify a single netflow source. See -n

       -l base_directory ( letter ell )
          Specifies  the  base  directory  to  store  the  output  files.   If a sub hierarchy is
          specified with -S the final directory is concatenated to  base_directory/sub_hierarchy.
          This  is  for  compatibility  with  nfdump  1.5.x  and used to specify a single netflow
          source. See -n

       -n <Ident,IP,base_directory>
          Configures a netflow source named Ident and identified by source IP  address  IP.   The
          base  directory  for  the flow files is base_directory. If a sub hierarchy is specified
          with -S the final directory is concatenated to  base_directory/sub_hierarchy.  Multiple
          netflow  sources  can  be specified. All data is sent to the same port specified by -p.
          Note: You must not mix -n option with -I and -l. Use either syntax.

       -M <dynbase_directory>
          Specifies the base directory to store the output files. In contrast to -l -M allows  to
          add  dynamically  new  flow  sources  (exporters),  as  they appear. All exporters send
          netflow data to the same port and  IP.   For  each  dynamically  added  source,  a  new
          directory  is  created  with the name of the IPv4/IPv6 address of the exporter. All '.'
          and ':" in IP addresses are replaced be '-'  e.g.  is  converted  to  the
          directory  name  10-11-12-13.   Note:  Please  make  sure to restrict at host level the
          potential range of IP addresses which are allowed to connect to nfcapd.  Otherwise  you
          risk a potential DoS attack on nfcapd, as nfcapd has no built in restrictions.

       -f <pcap_file>
          Read netflow packets from a give pcap_file instead of the network. This requires nfcapd
          to be compiled with the pcap option and is intended for debugging only.

       -s <rate>
          Apply default sampling rate rate to all netflow records, unless the  sampling  rate  is
          announced by the exporting device. In that case the announced sampling rate is applied.
          If <rate> is negative, this will hard overwrite any device specific announced  sampling

       -S <num>
          Allows  to  specify  an additional directory sub hierarchy to store the data files. The
          default is 0, no sub hierarchy, which means the files go directly in the base directory
          (-l).  The  base directory (-l) is concatenated with the specified sub hierarchy format
          to form the final data directory.  The following hierarchies are defined:
            0 default     no hierarchy levels
            1 %Y/%m/%d    year/month/day
            2 %Y/%m/%d/%H year/month/day/hour
            3 %Y/%W/%u    year/week_of_year/day_of_week
            4 %Y/%W/%u/%H year/week_of_year/day_of_week/hour
            5 %Y/%j       year/day-of-year
            6 %Y/%j/%H    year/day-of-year/hour
            7 %Y-%m-%d    year-month-day
            8 %Y-%m-%d/%H year-month-day/hour

       -T <extension list>
          Specifies the list of extensions, to be stored in the netflow file.  Regardless of  the
          extension  list,  the  following  netflow  data  is stored per record: first, last, fwd
          status, tcp flags, proto, (src)tos,  src  port,  dst  port,  src  ipaddr,  dst  ipaddr,
          in(packets),  in(bytes).  In  addition  nfcapd  recognises  the extensions as described
          below. Some are valid for v5/v7/v9, but most of  them  make  only  sense  for  v9.  Any
          specified extensions which do not exist in the input netflow records are ignored.

           v5/v7/v9/IPFIX extensions:
            1 input/output interface SNMP numbers.
            2 src/dst AS numbers.
            3 src/dst mask, (dst)TOS, direction.
            4 line Next hop IP addr line
            5 line BGP next hop IP addr line
            6 src/dst vlan id labels
            7 counter output packets
            8 counter output bytes
            9 counter aggregated flows
           10 in_src/out_dst MAC address
           11 in_dst/out_src MAC address
           12 MPLS labels 1-10
           13 Exporting router IPv4/IPv6 address
           14 Exporting router ID
           15 BGP adjacent prev/next AS
           16 time stamp flow received by the collector
           NSEL/ASA/NAT extensions
           26 NSEL     ASA event, xtended event, ICMP type/code
           27 NSEL/NAT xlate ports
           28 NSEL/NAT xlate IPv4/IPv6 addr
           29 NSEL     ASA ACL ingress/egress acl ID
           30 NSEL     ASA username
           NEL/NAT extensions
           31 NAT event, ingress egress vrfid
           32 NAT Block port allocation - block start, end step and size
           latency extension
           64 nfpcapd/nprobe client/server/application latency"},

           IMPORTANT:  By  default  only  extension  1  and  2  are  selected  Extensions  can be
           added/deleted by specifying a ',' separated list of extension  ids.  Each  id  may  be
           prepended by an optional sign +/- to add or remove a given id from the extension list.
           Shortcuts: The string 'all' means all extensions. The strings
            'nsel' and 'nel' enable all NSEL or NEL extensions respectively.

           -T all       Enables all possible extensions.
           -T +3,+4     Adds extensions 3 and 4 to the defaults 1 and 2.
           -T all,-8,-9 Set all extensions but 8 and 9
           -T -1,4      Removes default extension 1 and adds extension 4
           -T nsel      Enables all required ASA?NSEL extensions
           -T nel       Enables all required nell extensions
           Note: Only those tags in common with the exporting device and  enabled  extensions  at
           the  collector  side are stored into the data files. A detailed list which v9 tags are
           mapped into which extensions is given in the section NOTES

       -t interval
          Specifies the time interval in seconds to rotate files. The default  value  is  300s  (
          5min ).

       -w Align  file  rotation  with  next  n  minute ( specified by -t ) interval.  Example: If
          interval is 5 min, sync at 0,5,10... wall clock minutes Default: no alignment.

       -x cmd
          Run command cmd at the end of every interval, when a new file  becomes  available.  The
          following command expansion is available:
           %f   Replaced by the file name e.g nfcapd.200907110845 inluding any
                sub hierarchy. ( 2009/07/11/nfcapd.200907110845 )
           %d   Replaced by the directory where the file is located.
           %t   Replaced by the time ISO format e.g. 200907110845.
           %u   Replaced by the UNIX time format.
           %i   Replaced ident string given by -I

       -X Collect  and embed extended statistics. Currently a port and bpp histogram is embedded.
          Mostly experimental for now

       -e Auto expire files at every cycle. max lifetime  and  max  filesize  are  defined  using

       -P pidfile
          Specify name of pidfile. Default is no pidfile.

       -D Daemon  mode: fork to background and detach from terminal.  Nfcapd terminates on signal
          TERM, INT and HUP.

       -u userid
          Change to the user userid as soon as possible. Only root is allowed to use this option.

       -g groupid
          Change to the group groupid as soon as possible. Only root is allowed use this option.

       -B bufflen
          Specifies the socket input buffer length in bytes. For high volume traffic  (  near  GB
          traffic ) it is recommended to set this value as high as possible ( typically > 100k ),
          otherwise you risk to lose packets. The default is OS ( and kernel )  dependent.

       -E Print netflow records in nfdump raw format to stdout.  This  option  is  for  debugging
          purpose only, to see how incoming netflow data is processed and stored.

       -j Compress  flows.  Use  bz2  compression  in  output  file.  Note: not recommended while

       -y Compress flows. Use LZ4 compression in output file.

       -z Compress flows. Use fast LZO1X-1 compression in output file.

       -V Print nfcapd version and exit.

       -h Print help text to stdout with all options and exit.


       Returns 0 on success, or 255 if initialization failed.


       nfcapd logs to syslog with SYSLOG_FACILITY LOG_DAEMON For normal operation level 'warning'
       should be fine.  More information is reported at level 'info' and 'debug'.

       A  small statistic about the collected flows, as well as errors are reported at the end of
       every interval to syslog with level 'info'.


       All flows are sent to port 9995 from all exporters and stored  into  a  single  file.  All
       known v9 tags are taken.
              nfcapd   -z   -w   -D   -T   all   -l   /netflow/spool/allflows  -I  any  -S  2  -P

       All flows from 2 different exporters  are  sent  to  port  8877  and  stored  in  separate
       directory trees. All known v9 tags are taken. Input buffer size is set to 128000 bytes
              nfcapd  -z  -w -D -T all -p 8877 -n upstream,,/netflow/spool/upstream -n
              peer,,/netflow/spool/peer -S 2 -B 128000

       Only accept from from a single exporter and only extension 3,4 and 5 are accepted.  Run  a
       given command when files are rotated and automatically expire flows:
              nfcapd  -w  -D -T 3,4,5 -n upstream,,/netflow/spool/upstream -p 23456 -B
              128000 -s 100 -x '/path/command -r %d/%f'  -P /var/run/nfcapd/ -e


       Multiple netflow sources:

       Netflow data may be sent from different exporters to a single nfcapd process.  Use the  -n
       option  to  separate each netflow source to a different data directory.  For compatibility
       with nfdump 1.5.x, old style -l/-I options are still valid.  In that case all  flows  from
       all  sources  are  stored  in  a single file. For high volume netflow streams, it is still
       recommended to have a single nfcapd process per netflow source.

       The current v9 implementation of nfdump supports the following v9 elements: fields:
           v9 element          v9 ID     Extension
           NF9_LAST_SWITCHED      21       default
           NF9_FIRST_SWITCHED     22       default
           NF9_IN_BYTES            1       default
           NF9_IN_PACKETS          2       default
           NF9_IN_PROTOCOL         4       default
           NF9_SRC_TOS             5       default
           NF9_TCP_FLAGS           6       default
           NF9_FORWARDING_STATUS  89       default
           NF9_IPV4_SRC_ADDR       8       default
           NF9_IPV4_DST_ADDR      12       default
           NF9_IPV6_SRC_ADDR      27       default
           NF9_IPV6_DST_ADDR      28       default
           NF9_L4_SRC_PORT         7       default
           NF9_L4_DST_PORT        11       default
           NF9_ICMP_TYPE          32       default
           NF9_INPUT_SNMP         10             1
           NF9_OUTPUT_SNMP        14             1
           NF9_SRC_AS             16             2
           NF9_DST_AS             17             2
           NF9_DST_TOS            55             3
           NF9_DIRECTION          61             3
           NF9_SRC_MASK            9             3
           NF9_DST_MASK           13             3
           NF9_IPV6_SRC_MASK      29             3
           NF9_IPV6_DST_MASK      30             3
           NF9_V4_NEXT_HOP        15             4
           NF9_V6_NEXT_HOP        62             4
           NF9_BGP_V4_NEXT_HOP    18             5
           NF9_BPG_V6_NEXT_HOP    63             5
           NF9_SRC_VLAN           58             6
           NF9_DST_VLAN           59             6
           NF9_OUT_PKTS           24             7
           NF9_OUT_BYTES          23             8
           NF9_FLOWS_AGGR          3             9
           NF9_IN_SRC_MAC         56            10
           NF9_OUT_DST_MAC        57            10
           NF9_IN_DST_MAC         80            11
           NF9_OUT_SRC_MAC        81            11
           NF9_MPLS_LABEL_1       70            12
           NF9_MPLS_LABEL_2       71            12
           NF9_MPLS_LABEL_3       72            12
           NF9_MPLS_LABEL_4       73            12
           NF9_MPLS_LABEL_5       74            12
           NF9_MPLS_LABEL_6       75            12
           NF9_MPLS_LABEL_7       76            12
           NF9_MPLS_LABEL_8       77            12
           NF9_MPLS_LABEL_9       78            12
           NF9_MPLS_LABEL_10      79            12
           NF9_SAMPLING_INTERVAL  34            Sampling
           NF9_SAMPLING_ALGORITHM 35            Sampling
           NF9_FLOW_SAMPLER_ID    48            Sampling
           FLOW_SAMPLER_MODE      49            Sampling
           NF9_FLOW_SAMPLER_RANDOM_INTERVAL 50  Sampling
           IP addr of exporting router          13
           NF9_ENGINE_TYPE        38            14
           NF9_ENGINE_ID          39            14
           NF9_BGP_ADJ_NEXT_AS   128            15
           NF9_BGP_ADJ_PREV_AS   129            15
           collector received timestamp         16
       32 and 64 bit are supported for all counters. 32it AS numbers are supported.

       IPFIX support is experimental. Due to lack of implementation of  sampling  in  many  IPFIX
       exporters, sampling for IPFIX is not yet supported.

       The format of the data files is netflow version independent.

       Socket  buffer:  Setting  the  socket  buffer size is system dependent.  When starting up,
       nfcapd returns the number of bytes the buffer was actually set. This is  done  by  reading
       back the buffer size and may differ from what you requested.


       nfdump(1), nfprofile(1), nfreplay(1)


       No software without bugs! Please report any bugs back to me.

                                            2009-09-09                                  nfcapd(1)