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flow-nfilter(1)                      General Commands Manual                      flow-nfilter(1)

NAME

       flow-nfilter — Filter flows.

SYNOPSIS

       flow-nfilter  [-hk]   [-b  big|little]   [-C comment]  [-d debug_level]  [-f filter_fname]
       [-F filter_definition]  [-v variable binding]  [-z z_level]

DESCRIPTION

       The flow-nfilter utility will filter flows based on user selectable criteria.  Filters are
       defined  in  a  configuration  file  and  are  composed  of  primitives  and a definition.
       Definitions contain match lines grouped to form logical AND and OR operations on the  flow
       using  the  selected  primitives.   A definition may contain the invert command which will
       invert the result of the evaluation.

       Words in the configuration file of the form @VAR or @{VAR:-default} will  be  expanded  at
       run-time by setting variable names with the -v option.

       Filter  primitives  begin  with  the filter-primitive keyword followed by a symbolic name.
       Each primitive has a type defined below.  A list of permit and or deny  keywords  followed
       by  an  argument are later evaulated to determine if the flow is permitted or denied.  The
       default action for a primitive is to deny which may be changed with the  default  keyword.
       Symbolic substitutions are done where appropriate.

       The match keyword in a definition selects the criteria to match a primitive.  A match type
       may allow more than one type of primitive, for example the  src-ip-addr  match  type  will
       accept any of {ip-address, ip-address-mask, ip-address-prefix} primitive types.

        Primitive type          Type       Description/Example
       -------------------------------------------------------------------
       as                      Bucket     Autonomous System Number.
                                          600,159,3112

       ip-address-prefix-len   Numeric    Integer from 0 to 32.
                                          16-31

       ip-protocol             Bucket     Integer from 0 to 255.
                                          6,17,1

       ip-tos                  Bucket     Integer from 0 to 255 with mask.
                                          0xA0/0xE0

       ip-tcp-flags            Bucket     Integer from 0 to 255 with mask.
                                          0x2/0x2

       ifindex                 Bucket     Integer from 0 to 65535
                                          0,5,10

       engine                  Bucket     Integer from 0 to 255.
                                          0

       ip-port                 Bucket     Integer from 0 to 65535.
                                          80,8080,23,22

       ip-address              Hash       List of IP Addresses.
                                          10.0.0.1

       ip-address-mask         List       List of IP address/mask pairs.
                                          10.1.0.0 255.255.0.0

       ip-address-prefix       Trie       List of IP address/mask pairs.
                                          10.1/16

       tag                     Hash       List of tags.
                                          0xFF00

       tag-mask                List       List of tags.
                                          0xF000/0xFF00

       counter                 List       List of Integers with qualifier.
                                          lt 32

       time                    List       List of relative time specifiers.
                                          gt 5:00

       time-date               List       List of absolute time specifiers.
                                          gt December 12, 2002 5:13:21

       double                  List       List of doubles with qualifier.
                                          lt 32.0

       rate                    Element    Rate is calculated as 1/rate.
                                          permit 100

       Match type              Description             Primitives accepted
       -------------------------------------------------------------------
       source-as               Source AS               as

       destination-as          Destination AS          as

       ip-source-address       Source IP Address       ip-address,
                                                       ip-address-mask,
                                                       ip-address-prefix

       ip-destination-address  Destination IP Address  ip-address,
                                                       ip-address-mask,
                                                       ip-address-prefix

       ip-exporter-address     Exporter IP Address     ip-address,
                                                       ip-address-mask,
                                                       ip-address-prefix

       ip-nexthop-address      NextHop IP Address      ip-address,
                                                       ip-address-mask,
                                                       ip-address-prefix

       ip-shortcut-address     Shortcut IP Address     ip-address,
                                                       ip-address-mask,
                                                       ip-address-prefix

       ip-protocol             IP Protocol             ip-protocol

       ip-source-address-prefix-len
                               Source IP address       ip-address-prefix-len
                               prefix length

       ip-destination-address-prefix-len
                               Destination IP address  ip-address-prefix-len
                               prefix length

       ip-tos                  IP Type Of Service      ip-tos

       ip-marked-tos           IP Type Of Service      ip-tos

       ip-tcp-flags            IP/TCP Flags            ip-tcp-flags

       ip-source-port          Source IP Port          ip-port
                               eg TCP/UDP

       ip-destination-port     Destination IP Port     ip-port
                               eg TCP/UDP

       input-interface         Source ifIndex          ifindex
                               eg Input Interface

       output-interface        Destination ifIndex     ifindex
                               eg Output Interface

       start-time              Start Time of flow      time, time-date

       end-time                End Time of Flow        time, time-date

       flows                   Number of flows         counter

       octets                  Number of octets        counter

       packets                 Number of packets       counter

       duration                Duration of flow in ms  counter

       engine-id               Engine ID               engine

       engine-type             Engine Type             engine

       source-tag              Source Tag              tag, tag-mask

       destination-tag         Destination Tag         tag, tag-mask

       pps                     Packets Per Second      double

       bps                     Bits Per Second         double

       random-sample           Random Sample           rate

OPTIONS

       -b big|little
                 Byte order of output.

       -C Comment
                 Add a comment.

       -d debug_level
                 Enable debugging.

       -f filter_fname
                 Filter list filename.  Defaults to /etc/flow-tools/cfg/filter.

       -F filter_definition
                 Select the active definition.  Defaults to default.

       -h        Display help.

       -k        Keep time from input.

       -v variable binding
                 Set a variable FOO=bar.

       -z z_level
                 Configure  compression  level to  z_level.  0 is disabled (no compression), 9 is
                 highest compression.

TIME/DATE parsing

       time-date parsing is implemented with getdate.y, a commonly used function to process free-
       form time date specifications.  Example usage borrowed from cvs:
           1 month ago
           2 hours ago
           400000 seconds ago
           last year
           last Monday
           yesterday
           a fortnight ago
           3/31/92 10:00:07 PST
           January 23, 1987 10:05pm
           22:00 GMT

EXAMPLES

       An example of filter configuration file.

        filter-primitive srate
         type rate
         permit 100

       filter-primitive test-as
         type as
         permit 600,159

       filter-primitive test-prefix-len
         type ip-address-prefix-len
         permit 32

       filter-primitive test-protocol
         type ip-protocol
         permit tcp

       filter-primitive test-tos
         type ip-tos
         mask 0xA0
         permit 0xE0

       filter-primitive test-tcp-flags
         type ip-tcp-flags
         mask 0x2
         permit 0x2

       filter-primitive test-ifindex
         type ifindex
         permit 0,5,10

       filter-primitive test-engine
         type engine
         permit 0

       filter-primitive test-port
         type ip-port
         permit https
         permit 80
         default deny

       filter-primitive test-address
         type ip-address
         permit 0.0.0.1
         permit 0.0.0.2
         default deny

       filter-primitive test-address-mask
         type ip-address-mask
         permit 128.146.197.1 255.255.255.255
         permit 128.146.197.2 255.255.255.255

       filter-primitive test-prefix
         type ip-address-prefix
         permit 128.146.0.0/16
         default deny

       filter-primitive test-tag
         type tag
         permit 0x00
         permit 0x01
         permit 0xFF

       filter-primitive test-tag-mask
         type tag-mask
         permit OSU 0xFF
         permit 0xFF 0xFF
         default deny

       filter-primitive test-counter
         type counter
         permit lt 5
         permit gt 10
         default deny

       filter-primitive test-time-date
         type time-date
         permit gt December 12, 2002 5:13:21

       filter-primitive test-time
         type time-date
         permit gt 12:15:00

       filter-definition sample-1-in-100
         match random-sample srate

       filter-definition t1
         match engine-type test-engine
         or
         match destination-tag test-tag-mask

       Display all flows with a destination port of 80 or source port of 25 (smtp) starting after
       Dec 12, 2001.  The file test is populated with the following:

       filter-primitive port80
         type ip-port
         permit 80

       filter-primitive port25
         type ip-port
         permit smtp

       filter-primitive dec12
         type time-date
         permit gt Dec 12, 2001

       filter-definition foo
         match ip-source-port port80
         match start-time dec12
         or
         match ip-destination-port port25
         match start-time dec12

       flow-cat flows | flow-nfilter -ftest -Ffoo | flow-print

FILES

         Configuration files:
           Symbols - /etc/flow-tools/sym/*.
           Tag - /etc/flow-tools/cfg/tag.cfg.
           Filter - /etc/flow-tools/cfg/filter.cfg.

BUGS

       None known.

AUTHOR

       Mark Fullmer maf@splintered.net

SEE ALSO

       flow-tools(1)

                                                                                  flow-nfilter(1)