nfdump(1)

NAME

nfdump – flow display and analysis program

SYNOPSIS

nfdump -r flowpath [-w outfile] [-f filterfile] [-C config] [-R filelist] [-M dirlist] [-O order] [-t timewin] [-c num] [-a] [-A aggregation] [-b] [-B] [-I] [-D nameserver] [-G geoDB] [-H torDB] [-s statistic] [-n num] [-o format] [-6] [-q] [-N] [-i ident] [-v flowfile] [-E flowfile] [-x flowfile] [-W workers] [-z=<compress>] [-J compress] [-X] [-Z] [-T] [-V] [-h] [filter]

DESCRIPTION

nfdump reads the flow data from one or more binary files, created by any nfdump collector nfcapd, nfpcapd and sfcapd. It processes and lists the flows in many different output formats and can create a wide range of statistics.

nfdump has a very powerful flow filter to process flows. The filter syntax is very similar to tcpdump, but adapted and extended for flow filtering. A flow filter may also contain arrays of many thousand IP addresses etc. to search for specific records.

nfdump can aggreagte flows according to a user defined number of elements. This masks certain elements and allows to sum up flow records matching the same values.

The combination of flow filtering and aggregation as input for any flow statistics allows complex flow processing. Pre-filtered and aggregated flow data may also be written back into a binary flow file, which again may be processed with nfdump

nfdump can enrich the listing of flows with geo location information and AS information, unless AS information is already available in the flow records. IP addresses can be tagged with a two letter country code, or with a longer location label containing the geographic region, country and city. The geo location and AS information is retrieved from the optional geoDB database, created by the geolookup program from the nfdump tools. geolookup uses the Maxmind database GeoDB or GeoLite2 to create a binary lookup database for nfdump Please check the geolooup(1) man page for more details.

The options are as follows:

-r flowpath

Reads flow records from this path. flowpath may be a single file, or a directory containing any number of flow files or sub directories. All files are processed in the order, as listed by the OS.

-w outfile

Writes all processed records into outfile instead of printing. The flowfile is a binary flow file and may be processed again with nfdump This can be useful to limit flows according to a flow filter and/or specific flow aggregation.

-f filterfile

Reads the flow filter from filterfile. This can be useful for very long or structured filters, with comments and long lists. Note: Any filter specified directly on the command line takes precedence over the filterfile.

-C config

Read more options from file config. nfdump tries to read by default %prefix/etc/nfdump.config. This may be overwritten by the environment valiable NFCONF which again may be overwritten by this option -C. In order to prevent reading any config file, even if it would exist set -C none. A config file is not required, but may be handy for often used output formats etc.

-O order

Sets an output order for records to be printed as text output. This order applies after all records processing, such as filtering, and aggregation and before printing.

flows

Sort according to the number of flows

packets

Sort according to (in)packets

ipkg

Same as packets

opkg

Sort according to output packets

bytes

Sort according to (in)bytes

ibyte

Same as bytes

obyte

Sort according to output bytes

pps

Sort according to (in)packets per second

ipps

Same as ipps

opps

Sort according to out packets per second

bps

Sort according to (in)bytes per second

ibps

Same as bps

obps

Sort according to output bytes per second

bpp

Sort according to (in)bytes per packet

ibpp

Same as bpp

obpp

Sort according to output packets

tstart

Sort according to start time of flow - former -m

tend

Sort according to end time of flows

duration

Sort according to duration of flows

-t timewin

Set time window to process flows. This option is considered legacy andmay be replaced with a filter primitive in future rleases. The time window is specified as: YYYY/MM/dd.hh:mm:ss[-YYYY/MM/dd.hh:mm:ss]. Any parts of the time spec may be omitted e.g YYYY/MM/dd expands to YYYY/MM/dd.00:00:00-infinity and processes all flow from a given day onwards. The time window may also be specified as +/- n. In this case it is relative to the beginning or end of all flows. +10 means the first 10 seconds of all flows, -10 means the last 10 seconds of all flows.

-c num

Limit the number of records to be processed to the first num records, which passwd the filter.

-a

Aggregate flow records. The default aggregation is done at connection level by taking the 5-tuple protocol, srcip, dstip, srcport and dstport. This way of aggregation may be overwritten by option -A

-A aggregation

Sets the list of elements in a flow record to be aggregated. aggregation is a ',' separated list of any number of v9/ipfix elements. The following elements are accepted:

proto

IP protocol

srcip

Source IP address

dstip

Destination IP address

srcip4/net

IPv4 source IP address with applied netmask

srcip6/net

IPv6 source IP address with applied netmask

dstip4/net

IPv4 destination IP address with applied netmask

dstip6/net

IPv6 destination IP address with applied netmask

srcnet

Apply netmask srcmask in netflow record for source IP

dstnet

Apply netmask dstmask in netflow record for dest IP

srcport

Source port

dstport

Destination port

srcmask

Source mask

dstmask

Destination mask

srcvlan

Source vlan label

dstvlan

Destination vlan label

srcas

Source AS number

dstas

Destination AS number

nextas

BGP Next AS

prevas

BGP Previous AS

inif

SNMP input interface number

outif

SNMP output interface number

next

IP next hop

bgpnext

BGP next hop

insrcmac

In source MAC address

outdstmac

out destination MAC address

indstmac

In destination MAC address

outsrcmac

Out source MAC address

tos

Source type of service

srctos

Source type of Service

dsttos

Destination type of Service

mpls1

MPLS label 1

mpls2

MPLS label 2

mpls3

MPLS label 3

mpls4

MPLS label 4

mpls5

MPLS label 5

mpls6

MPLS label 6

mpls7

MPLS label 7

mpls8

MPLS label 8

mpls9

MPLS label 9

mpls10

MPLS label 10

router

IP address of exporting router

odid

observation domain ID

opid

observation point ID

xsrcip

X-late source IP address, if compiled with NSEL support

xdstip

X-late destination IP address, if compiled with NSEL support

xsrcport

X-late source port, if compiled with NSEL support

xdstport

X-late destination port, if compiled with NSEL support

nfdump automatically compiles the appropriate output format for the selected aggregation elements unless an explicit output format -o is given. The automatic output format is identical to

-o 'fmt:%ts %td <fields> %pkt %byt %bps %bpp %fl'

where <fields> represents the selected aggregation tags.

-b

Aggregate flow records as bidirectional flows. This automatically implies -a. Aggregation is done on connection level by taking the 5-tuple protocol, srcip, dstip, srcport and dstport The reverse order applies for the corresponding reverse flow. Input and output packets/bytes are counted and reported separately. Both flows are merged into a single record with corresponding input and output counters. An appropriate output format is selected automatically, which may be overwritten by any -o format option.

-B

Similar to option -b but tries to guess the correct client to server direction. Automagically swaps flows if src port is < dst port for TCP and UDP flows and src port < 1024 and dst port > 1024. Some exporters do not really care sending the flows in proper order. It's considered to be a conveniency option.

-I

Print flow statistics of a single file or the summary of all the files specified by -r flowpath.

-g

Print for each flow file given by -r flowpath a one line summary, which can be easily used by gnu plot.

-D nameserver

Sets the nameserver to translate hostnames into IP addresses in filter expressions. See filter below for more details.

-G geoDB

Use geoDB as geo lookup DB for geo location and AS lookups. nfdump tries to read the environment variable NFGEODB for the path of geoDB. The option -G overwrites NFGEODB or geodb.path in nfdump.conf. In order to prevent reading any geoDB file, even if it would exist set -G none. See also geolookup(1)

-H torDB

Use torDB as tor lookup DB for tor exit node lookups. nfdump tries to read the environment variable NFTORDB for the path of torDB. The option -H overwrites NFTORDB or tordb.path in nfdump.conf. In order to prevent reading any torDB file, even if it would exist set -H none. See also torlookup(1)

-s statistic [:p [/orderby]]

Generate the Top N flow record or flow element statistic. By optionally adding :p to statistic, the statistic is additionally split up into the transport layer protocols. By default the statistic is transport protocol independent. Each statistic may be ordered by the optional parameter orderby This can be flows, packets, bytes, pps, bps or bpp. You may specify more than one orderby option, which results in the same statistic but ordered differently. If no orderby is given, the statistic is ordered by flows. You can specify as many -s flow element statistics as needed on the command line for the same run.

statistic can be:

record

aggregated netflow records.

srcip

source IP addresses

dstip

destination IP addresses

ip

any (src or dst) IP addresses

nhip

next hop IP addresses

nhbip

BGP next hop IP addresses

router

exporting router IP address

srcport

source ports

dstport

destination ports

port

any (source or destination) ports

tos

type of service - default src

srctos

src type of service

dsttos

dst type of service

dir

flow directions ingress/egress

srcas

source AS numbers

dstas

destination AS numbers

srcasn

source AS organisations and numbers

dstasn

destination AS organisations and numbers

srcgeo

2 letter geo source country code

dstgeo

2 letter geo destination country code

as

any (source or destination) AS numbers

asn

any (source or destination) AS org and numbers

inif

input interface

outif

output interface

if

any interface

inam

input interface name

onam

output interface name

srcmask

src mask

dstmask

dst mask

srcvlan

src vlan label

dstvlan

dst vlan label

vlan

any vlan label

insrcmac

input src MAC address

outdstmac

output dst MAC address

indstmac

input dst MAC address

outsrcmac

output src MAC address

srcmac

any src MAC address

dstmac

any dst MAC address

inmac

any input MAC address

outmac

any output MAC address

mask

any mask

proto

IP protocols

mpls1

MPLS label 1

mpls2

MPLS label 2

mpls3

MPLS label 3

mpls4

MPLS label 4

mpls5

MPLS label 5

mpls6

MPLS label 6

mpls7

MPLS label 7

mpls8

MPLS label 8

mpls9

MPLS label 9

mpls10

MPLS label 10

sysid

Internal SysID of exporter

nbar

nbar ID

ja3

ja3 hashes

odid

observation domain ID

opid

observation point ID

vrf/ivrf

ingress vrf

evrf

egress vrf

ivrfnam

ingress vrf name

evrfnam

egress vrf name

NSEL/ASA statistics

event

NSEL/ASA event

xevent

NSEL/ASA extended event

xsrcip

NSEL/ASA translated src IP address

xsrcport

NSEL/ASA translated src port

xdstip

NSEL/ASA translated dst IP address

xdstport

NSEL/ASA translated dst port

iacl

NSEL/ASA ingress ACL

iace

NSEL/ASA ingress ACE

ixace

NSEL/ASA ingress xACE

eacl

NSEL/ASA egress ACL

eace

NSEL/ASA egress ACE

exace

NSEL/ASA egress xACE

NAT statistics

nevent

NAT event

nsrcip

NAT src IP address

nsrcport

NAT src port

ndstip

NAT dst IP address

ndstport

NAT dst port

% nfdump -s srcip -s ip/flows/bytes -s record/bytes

-n num

Set the number of records to be printed to num. This option applies to -s statistics as well as to ordered output -O -or -aggregated -records -a The default is set to 10 for statistics and unlimited for the other use cases. To disable the limit, set num to 0.

-o format

Sets the output format to print flow records. has many different output formats already predefined. format may be one of the options below:

raw

Print the full flow record on multiple lines. This prints all available information.

fmt: user

Print the flow records according the format user. This is a very flexible and powerful way to format flow records. See the section OUTPUT below for more details on how to compile your own format.

csv: user

Print the flow records as user defined csv format. Use a ',' separated list of user defined output token compatible with fmt format. See the section OUTPUT below for more details on how to compile your own csv format.

json

Print full record as a separate json object.

ndjson

Print full record as a one line json object, sepatated by newline. Suitable for log processors such as logstash.

csv

Print reocrd in csv format - format compatible to fmt line format.

csv-fast

Replaces old pipe format. Basic record information only. Fast implementation.

Already predefined fmt formats:

line

Print each flow on one line. Default format.

long

Print each flow on one line with more details

biline

Same as line, but for bi-directional flows

bilong

Same as long, but for bi-directional flows

gline

Same as line, but add country code to IPs. If a geoDB file is supplied this is the default output format

glong

Same as long, but add country code to IPs

extended

Print each flow on one line with even more details.

nsel

Print format for NSEL event records. Default format if NSEL/NAT support has been compiled in.

nel

Print format for NAT event records.

The nfdump config file may contain additional formats. If you want to add new formats or change existing ones, check the config file.

IPv6 addresses are printed condensed in any fmt defined format to prevent cluttering the output with large blank blocks. A condensed IPV6 uses max 16 characters. If it is longer, then the middle part of the IP is cut out and replaced be "..". For previewing an output, this fits most needs. For a listing with the full IPV6 addresses add option -6.

-6

Print full length of IPv6 addresses in output instead of condensed.

-q

Quiet mode. Suppress the header line and the statistics at the bottom of text outputs.

-N

Print plain numbers in output without scaling. Easier for output parsing with 3rd party tools.

-i ident

Change the ident label in the file, specified by -r to ident

-v flowfile

Verify the consistency of flowfile and print the file parameters and number of records.

-E flowfile

Print the exporter and sampler list if found in flowfile. Additional statistics per exporter are printed with number of flows, packets and sequence errors.

-x flowfile

This options works on nfdump version 1.6.x files only and may get removed in future. Scans and prints extension maps located in flowfile

-z=lzo

Compress flow files with LZO1X-1 compression. Fastest compression.

-z=bz2

Compress flow files with bz2 compression. Slow but most efficient. May be used for archiving files or if you are really short of spce.

-z=lz4[:level]

Compress flow files with LZ4 compression. Fast and efficient. Optional level should be between 1..10 Changing the level results in smaller files but uses up more time to compress. Levels > 5 may need more workers. See -W.

-z=zstd[:level]

Compress flow files with ZSTD compression. Fast and efficient. Optional level should be between 1..10 Changing the level results in smaller files but uses up more time to compress. Levels > 5 may need more workers. See -W.

-W num

Sets the number of workers to compress flows. Defaults to 4. Must not be greater than the number of cores online. Useful for higher levels of compression for lz4 or zstd and large amount of flows per second. Please not, -W affects only writing flows.

-J compress

Change compression for any number of files given by option -r flowpath Set compress to 0 for no compression or to any of: 1 or LZO, 2 or BZ2, 3 or LZ4. This option may be used for archiving flow files and changing the compression to use less disk space.

-X

Compiles the filter syntax and dumps the filter engine table to stdout. This is for debugging purpose only.

-Z

Check filter syntax and exit. Sets the return value accordingly.

-R filelist

Select a range of files. This option is mainly used by old NfSen and documented here as legacy option.

/any/dir Read recursively all files in directory dir.

/dir/file Read all files beginning with file.

/dir/file1:file2 Read all files from file1 to file2.

When using in combination with a sub hierarchy: /dir/sub1/sub2/file1:sub3/sub4/file2 Read all files from sub1/sub2/file1 sub3/sub4/file2 iterating over all required hierarchy levels. Note: files are read in alphabetical order.

-M dirlist

Read the same file hierarchy from multiple directories. This option is mainly used by old NfSen and documented here as legacy option. Example: /any/path/to/dir1:dir2:dir3 etc. and will be expanded to the directories: /any/path/to/dir1, /any/path/to/dir2 and /any/path/to/dir3. Any number of colon separated directories may be given. A path ending with a wildcard '@' such as /any/path/to@ will expand automatically in a list of all existing sub directories /any/path/to/dir1:dir2:dir3. The files to read are specified by -r or -R and are expected to exist in all the given directories. The options -r and -R must not contain any directories when used in combination with -M.

-T

Tag IP addresses with a prepending cntrl-A character, to allow output parsers to hook in. This option is mainly used by old NfSen and documented here as legacy option.

-V

Print nfdump version and exit.

-h

Print help text on stdout with all options and exit.

filter selects, which records will be further processed. If no filter is given, all records will be processed. Otherwise, only those flows matching the filter will be processed. Any IP address in a filter may be specified as IPv4 or IPv6.

The filter syntax is similar to tcpdump but adapted and extended for flow records. The filter can be either specified on the command line after all options or in a separate file. It can span several lines. Anything after a '#' is treated as a comment and ignored to the end of the line. There is virtually no limit in the length of the filter expression. All keywords are case insensitive.

A single filter primitive filters a single element of a flow record. A filter consists of one or more primitives, which are linked together:

expr and expr

expr or expr

not expr and (expr)

In all expressions, where a number is a valid argument, the number may be given as a normal decimal number or as a hex number prefixed by 0x such as 0x22. A decimal number may also contain a multiplication factor such as K, M, G, T which multiplies the number by the corresponding factor. For example 1K, 2G etc.

String arguments may be single or double quoted or not quoted at all, if the string is not a reserved filter key word - src geo CH but src geo 'IN'

Possible filter primitives:

@include file

Expands the content of file into the current filter

count comp number

True if the comparison with the record counter matches number Each record gets assigned a record number at the time it is read from file. Therefore this record number is not unique and may change, depending on the order files are read.

ident string

True if the record ident field matches string. This filter can be used to filter out different sources.

inet

ipv4

True if source and destination IP of a record are IPv4 IPs.

inet6

ipv6

True if source and destination IP of a record are IPv6 IPs.

ttl comp num

True if IP ttl matches comparison.

proto protocol

True if the record protocol field matches protocol. protocol can be a string such as tcp, udp, icmp, ah, esp, ipip, and many more or a protocol number, such as 6, 17 for protocol tcp and udp.

tun proto protocol

True if the record tunnel protocol field matches protocol. protocol may be a string or protocol number.

ip ipaddr

src ip ipaddr

dst ip ipaddr

True if the respective IP field of the record matches ipaddr. ipaddr may be an IPv4 or IPv6 address or a symbolic hostname. In this case a DNS lookup resolves the hostname to one or more IP addresses. If more than one IP results, all IPs are chained together in an or chain. (IP or IP or IP). If ip is not specified with src or dst the source or destination IP may match. If ipaddr is set to tor then flows are listed, if the respective ip addr is a to tor exit not. For this filter to work, you need a working nftordb.

host ipaddr

host is just a synonym for ip (See above)

ip in [iplist]

src in ip [iplist]

dst ip [iplist]

True if the respective IP field of the record is in iplist. iplist is a space or ',' separated list of IP addresses or networks in CIDR notation. This is the preferred way to search in large list of IP addresses and networks and is much more efficient than to chain all IP addresses together. (IP1 or IP2 or IP3). The iplist may contain several hundreds to thousand IPs and/or networks. For just a few IPs use an or chain, otherwise use an iplist If ip is not specified with src or dst the source or destination IP may match.

net network netmask

src net network netmask

dst net network netmask

net network/netbits

src net network/netbits

dst net network/netbits

True if the respective IP field of the record matches the network if the corresponding netmask or netbits are applied to the IP address. If net is not specified with src or dst the source or destination IP may match.

geo string

src geo string

dst geo string

True, if the 2-letter country code resolved by geolookup of the source or destination IP address matches string. This filter works only, if a valid geoDB is specified. See geo location option above. The 2-letter country code corresponds to the maxmind DB definitions. if geo is not specified with src or dst the source or destination geo location code may match. Please note: country codes, which match nfdump filter language reserved words such as IN, LT etc must be explicitly quoted to be recoginzed as string.

tunip ipaddr

src tunip ipaddr

dst tunip ipaddr

True if the respective tunnel IP field of the record matches ipaddr. If tunip is not specified with src or dst the source or destination tunnel IP may match.

port comp num

src port comp num

dst port comp num

True if the comparison of the respective port field matches num See comp for the comparator details. If port is not specified with src or dst the source or destination port may match.

port in [portlist]

src port in [portlist]

dst port in [portlist]

True if the respective port field of the record is in portlist. portlist is a space or ',' separated list of port numbers. This is the preferred way to search in large list of port numbers and is much more efficient than to chain all ports together. (PORT1 or PORT2 or PORT3). portlist may contain several hundreds to thousand of port numbers. If port is not specified with src or dst the source or destination port may match.

icmp type num

icmp code num

True if the respective icmp field of the record matches num. This automatically implies proto icmp.

engine type num

engine id num

sysid num

True if the respective fields of the record matches num engine type and ID are set by the exporting device, sysid refers to the nfdump collector internal assigned number. See also option -E above.

if num

in if num

out if num

True if the respective interface fields of the record matches num. This ID may correspond to the SNMP ID of the interface but depends on the exporter. If if is not specified with in or out the input or output interface may match.

as comp num

src as comp num

dst as comp num

prev as comp num

next as comp num

True if the comparison of the respective AS fields matches nfdump supports 32-bit AS numbers every where. Without or the source or destination AS may match. See comp for the comparator details.

as in [aslist]

src as in [aslist]

dst as in [aslist]

prev as in [aslist]

next as in [aslist]

True if the respective AS field of the record is in aslist. aslist is a space or ',' separated list of AS numbers. This is the preferred way to search in large list of AS numbers and is much more efficient than to chain all ports together. aslist may contain several hundreds to thousand of AS numbers. If as is not specified with src, dst, prev or next the source or destination AS may match.

mask bits

src mask bits

dst mask bits

True if the respective mask bit field of the record matches bits If mask is not specified with src or dst the source or destination mask bits may match.

vlan num

src vlan num

dst vlan num

True if the respective vlan field of the record matches num If vlan is not specified with src or dst the source or destination vlan may match.

flags tcpflags

True if the respective tcp flags field of the record matches any of the given tcpflags. tcpflags is a string combination of all flags to be tested:

A

ACK.

S

SYN.

F

FIN.

R

Reset.

P

Push.

U

Urgent.

X

All flags on.

The order of the flags within tcpflags is not relevant. Flags not mentioned are treated as don't care. In order to get those flows with only the SYN flag set, use the syntax

flags S and not flags AFRPU

router ip ipaddr

True if the ip address of the sending router matches ipaddr as valid IPv4/IPv6 address.

next ip ipaddr

True if the field next-ip of the record matches ipaddr as valid IPv4/IPv6 address.

bgp next ip ipaddr

True if the field bgpnext-ip of the record matches ipaddr as valid IPv4/IPv6 address.

mac macaddr

in mac macaddr

in src mac macaddr

in dst mac macaddr

out mac macaddr

out src mac macaddr

out dst mac macaddr

True if the respective mac address field of the record matches macaddr By prepending mac with any combination of a direction specifier as defined by CISCO v9 the test is limited to those mac addresses only. Otherwise multiple matches are possible. Without any specifiers any mac address is tested against macaddr

mpls labelN comp number

True if the comparison of the mpls label N with N as mpls label number 1..10 matches number Filters according a specific number in the mpls label stack.

mpls eos comp number

True if the comparison of the end of stack mpls label matches number

mpls expN comp number

True if the comparison of the experimental bits 0..7 of mpls label N with N as mpls label number 1..10 matches number

packets comp num

in packets comp num

out packets comp num

True if the comparison of the packet counter in the flow record matches num. num may contain any valid scaling factor such as k, m, g Example: packets > 1k. For a single flow packets and in packets is equivalent and describes the number of packets from source to destination. In case of a bi-directional flow (sent by an exporter or combined by option --B ) the packet counter for the reverse flow can be tested with out packet

bytes comp num

in bytes comp num

out bytes comp num

True if the comparison of the byte counter in the flow record matches num. num may contain any valid scaling factor such as k, m, g Example: bytes > 1k bytes and in bytes is equivalent and describes the number of bytes from source to destination. In case of a bi-directional flow (sent by an exporter or combined by option --B ) the byte counter for the reverse flow can be tested with out bytes

flows comp num

True if the comparison of the flow counter in the flow record matches num. num may contain any valid scaling factor such as k, m, g For each received flow, the flow counter is set to 1, unless the exporter sends this information. If multiple flows are aggregated, this counter is increased respectively.

tos num

True if the type of service field of the flow record matches num

flowdir direction

True, if the flow direction field in the flow record matches direction. direction may be ingress, egress, 0 for ingress, or 1 for egress

duration comp time

True if the calculated duration of a flow (tend - tstart) compares to time. The duration is specified in msec (milliseconds)

pps comp num

True if the calculated value of in-packets/duration (packets per second) compares with the number num. num may contain any valid scaling factor such as k, m, g

bps comp num

True if the calculated value of 8*in-bytes/duration (bits per second) compares with the number num. num may contain any valid scaling factor such as k, m, g

bpp comp num

True if the calculated value of in-bytes/in-packets (bytes per packet) compares with the number num. num may contain any valid scaling factor such as k, m, g

observation domain id comp number

observation point id comp number

True if the comparison of the observation domain ID or point ID field respectively matches number

payload filters

Some exporters, such as yaf or the nfdump collector nfpcap can send payload data along the netflow information. If such payloads are sent it can be filtered according the filter primitives below:

payload content 'string'

True if the string string is found in the payload data. string must be quoted with single or double quotes: 'string', “string”

payload regex 'regex'

payload regex 'regex' flags

True if regex matches the payload data. regex searches over the full payload length. A ' ' byte does not stop the match process. regex must be quoted with single or double quotes: 'regex' or “regex” The regex engine understands the following reduced syntax:

(...) subexpressions/capture ranges

| the "or" operator

^and $ anchors

[...] and [^...] character classes

?, *, +, simple quantifiers

*?, +?, ?? lazy quantifiers

{<num>}, {<num1>,<num2>} complex quantifiers

flags are optional can be:

m multiline

i case insensitive matching

s

payload ssl defined

True, if the payload contains the start of a valid SSL/TLS handshake

payload ssl version version

True, if the payload contains the start of a valid SSL handshake and the SSL/TLS version matches version Valid versions are 1.0, 2.0, 3.0

payload tls version version

True, if the payload contains the start of a valid TLS handshake and the TLS version matches version Valid versions are 1.0, 1.1, 1.2, 1.3

payload tls sni sniname

True, if the payload contains the start of a valid TLS handshake and the TLS sni name contains the string sniname

payload ja3 md5string

True, if the payload contains the start of a valid SSL/TLS handshake and the calculated ja3 value of the handshake matches md5string Depending on client or server SSL handshake, either ja3 or ja3s is calculated.

payload ja3 defined

True, if the payload contains the start of a valid SSL/TLS handshake and a valid ja3 value can be calculated. Useful to mask out all flow records with no SSL/TLS traffic in order to generate a -s ja3 statistic

payload ja4 ja4string

True, if the payload contains the start of a valid SSL/TLS handshake and the calculated ja4 value of the client TLS handshake matches ja4string

payload jas4 ja4Sstring

True, if the payload contains the start of a valid SSL/TLS handshake and the calculated ja4 value of the server TLS handshake matches ja4Sstring

payload ja4 defined

True, if the payload contains the start of a valid SSL/TLS handshake and a valid ja4/ja4s value can be calculated. Useful to mask out all flow records with no SSL/TLS traffic in order to generate a -s ja3 or a -s ja3s statistic

OpenBSD pflog implemented elements

pf action action

True, if the respective pflog action field compares to one of pass, block, scrub, noscrub, nat, nonat, binat, nobinat, rdr, nordr, synblock, defer, match, divert, rt, afrt

pf reason reason

True, if the respective pflog reason field compares to one of match, bad-offset, fragment, short, normalize, memory, bad-timestamp, congestion, ip-option, proto-cksum, state-mismatch, state-insert, state-limit, src-limit, synproxy, translate, no-route

pf rule ruleNr

True, if the respective pflog rule number field matches ruleNr

pf dir in|out

True, if the respective pflog rule direction field matches in or out

pf interface interfaceName

True, if the respective pflog rule interface name field matches the string interfaceName

nprobe implemented elements

client latency comp time

server latency comp time

True, if the respective latency field in the flow record compares to time. time is specified in msec.

CISCO ASA, network security event logging (NSEL) and NAT event logging (NEL) specific filters:

NSEL specific filters:

asa event event

True if the NSEL event type of an event record matches event which may be: ignore, create, term, delete, deny

asa event comp number

True if the comparison of the NSEL event type of an event records matches number as a number.

asa event denied reason

True if the event denied type of an event records matches reason which may be ingress, egress, interface, nosyn

asa xevent comp num

True, if the comparison of the extended event field of the event record matches num

xip ipaddr

src xip ipaddr

dst xip ipaddr

True, if the field of the translated source or destination IP address matches ipaddr if xip is specified without src or dst both IP addresses may match.

xport ipaddr

src xport ipaddr

dst xport ipaddr

True, if the field of the translated source or destination IP address matches ipaddr if xport is specified without src or dst both ports may match.

xnet network/mask

src xnet network/mask

dst xnet network/mask

True if the translated source or destination IP address matches network if mask mask is applied. if xnet is specified without src or dst both IP addresses may match.

ingress ACL comp number

ingress ACE comp number

ingress XACE comp number

True if the comparison of the respective ingress field matches number

egress ACL comp number

True if the comparison of the egress field matches number

NEL specific filters:

nat event event

True if the NEL event type of an event record matches event. event may be add, delete

nat event comp number

True if the comparison of the NEL event type of an event records matches number as a number.

nip ipaddr

src nip ipaddr

dst nip ipaddr

True, if the field of the nat source or destination IP address matches ipaddr if nip is specified without src or dst both IP addresses may match.

It Cm nport Ar number

src nport number

dst nport number

True, if the field of the nat source or destination port matches number if nip is specified without src or dst both ports may match.

ingress vrf number

True, if the field of the ingess vrf field of the event record matches number

pblock start comp number

pblock step comp number

pblock end comp number

True if the comparison of the start, step or end of the NAT port block in the event record matches number

port in pblock

src port in pblock

dst port in pblock

True, if the source or destination port field matches the NAT port block range

comp

Many filter elements support the comparison with a number. The following comparators are supported for each of those filters: =, ==, >, <, >=, <= To prevent collisions with bash interpretation, alternative comparators are available: EQ, LT, GT, LE, GE If comp is omitted, '==' is assumed.

OUTPUT FORMAT

This section describes how output formats are compiled. nfdump has a lot of already pre-defined output formats such as raw, json, ndjson, csv etc. One line formats supplied with option -o can be compiled from various elements of a flow record. As a flow record contains many different elements it is often useful to compile an output format for specific needs.

-o “fmt:%ts %td %pr %sap -> %dap %pkt %byt %fl”

-o “csv:%ts,%td,%pr,%sa,%sp,%da,%dp,%pkt,%byt,%fl”

-o “fmt:%long %ra”

fmt.newname = “fmt:%ts %td %pr %sap -> %dap %pkt %byt %fl”

csv.newname = “csv:%tsr,%ter,%pr,%sa,%sp,%da,%dp,%pkt,%byt,%fl”

EXAMPLES

nfdump processes files created by any previous version of nfdump 1.6.x with some limitations for versions < 1.6.17. In order to convert flow files to the new 1.7.x binary format use the following command to read//write files:

% nfdump -r oldfile -w newfile

Print a statistic about the top 20 IP addresses, once sorted by flows and once by bytes

% nfdump -r flowfile -s ip/flows/bytes -n 20

Print two statistics, one about the source IP and one about the destination IP address limited to flow with either source or destination port 443

% nfdump -r flowfile -s srcip/bytes -s dstip/bytes -n 20 'port 443'

Print a statistic about the IP pairs, which exchanged most traffic.

% nfdump -r flowfile -s record/bytes -A srcip,dstip

Print all flows in raw format with a HTTP header in the payload even if flow is not on port 80.

% nfdump -r flowfile -o raw “payload regex 'GET|POST'”

Print a statistic about all ja3 md5 sums for those flows, which a valid ja3 can be calculated

% nfdump -r flowfile -s ja5 -n 0 'payload ja3 defined'

Aggregate all flows and write the result back to a binary file, sorted by the start time

% nfdump -r flowfile -a -Otstart -w newfile

RETURN VALUES

nfdump returns 0 on success and 255 if processing failed.

SEE ALSO

https://www.iana.org/assignments/ipfix/ipfix.xhtml

https://www.cisco.com/en/US/technologies/tk648/tk362/technologies_white_paper09186a00800a3db9.html

nfcapd(1) nfpcapd(1) sfcapd(1) geolookup(1)

BUGS

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