Man page - nfdump(1)
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NFDUMP (1) General Commands Manual 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
ˆand $
anchors
[...]
and
[ˆ...]
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.
Format description
The output format is specified by -o “
fmt:
string
” for line output or
-o
“
csv:
string
” for csv output.
String
contains the field
tags
to be printed as well as
other characters if needed. A
tag
starts with a
%
sign followed by the field name.
tags
are
separated by spaces for line format or by ’,’
for csv format. Characters or other strings, not starting
with a
%
sign are copied literally to the output.
Example:
-o “
fmt:%ts %td %pr %sap -> %dap %pkt %byt %fl ”
-o “
csv:%ts,%td,%pr,%sa,%sp,%da,%dp,%pkt,%byt,%fl ”
The difference between fmt and csv is the printing of the header line. Furthermore csv does not have a flow summary at the end. csv output can be processed by any other post processing tool, which understands csv data. The examples above show the definitions of the predined formats line and csv. It adds the elements tstart duration protocol source IP address/port followed by the literal characters -> and destination ip address/port packets, bytes, flows counter. Depending on the task, different output formats are required to see the required fields of a flow record. You can either extend a predefined format or specify a new one at the command line.
Example: Extend the predefined format long with the the IP address of the sending router
-o “
fmt:%long %ra ”
Predefined formats can be extended by simply add their name with a % sign somewhere in the format string. As described under the output option -o
Format definition
nfdump has already many formats predefined. Most of the time, these format are good enough. Sometimes you may need different formats, which can be compiled as described above. In order to prevent adding the same often used output format each time you run nfdump a new output format may be define in the config file nfdump.conf The file nfdump.conf.dist contains the definition of the already hard coded formats. These may be uncommented and changed according to the specific needs. New formats may be added using the following syntax:
fmt.newname = “
fmt:%ts %td %pr %sap -> %dap %pkt %byt %fl ”
with newname any new or existing definition of output formats. Existing formats are overwritten with the new definition. You may also define a custom csv output format such as:
csv.newname = “
csv:%tsr,%ter,%pr,%sa,%sp,%da,%dp,%pkt,%byt,%fl ”
Please note, that newname must be unique for all formats in fmt as well as csv
Tag definition
The following list contains all tags, which are available to compile the output format:
%<format>
Inserts the predefined format at this position. e.g. %line
%cnt
Record counter. record numbers are assigned dynamically assigned while reading read from file.
%nfv
Netflow version.
%ts
Start Time - first seen
%tfs
First seen - identical to %ts
%tsr
Start Time, but in fractional seconds since the epoch (1970-01-01) UNIX format.
%tsg
Start Time GMT - first seem
%te
End Time - last seen
%ter
End Time, in fractional seconds
%teg
End Time GMT - last seen
%tr
Time the flow was received by the collector
%trr
Time the flow was received, in fractional seconds
%trg
Time GMT the flow was received by the collector
%td
Duration of flow. Displayed in ddHHMMSS.msec
%pr
Transort protocol
%exp
Exporter ID
%eng
Engine Type/ID
%lbl
Flowlabel
%sa
Source Address
%da
Destination Address
%sap
Source Address:Port
%dap
Destination Address:Port
%gsap
Source Address(country code):Port
%gdap
Destination Address(country code):Port
%sp
Source Port
%dp
Destination Port
%ttl
IP ttl
%it
ICMP-type
%ic
ICMP-code
%sn
Source Network, mask applied
%dn
Destination Network, mask applied
%nh
Next-hop IP Address
%nhb
BGP Next-hop IP Address
%ra
Router IP Address
%sas
Source AS
%das
Destination AS
%nas
Next AS
%pas
Previous AS
%in
Input Interface num
%out
Output Interface num
%pkt
Packets - default input
%ipkt
Input Packets
%opkt
Output Packets
%byt
Bytes - default input
%ibyt
Input Bytes
%obyt
Output Bytes
%fl
Flows
%flg
TCP Flags
%tos
Tos - default src
%stos
Src Tos
%dtos
Dst Tos
%dir
Direction: ingress, egress
%smk
Src mask
%dmk
Dst mask
%fwd
Forwarding Status
%svln
Src vlan label
%dvln
Dst vlan label
%scvln
Src customer vlan label
%dcvln
Dst customer vlan label
%ismc
Input Src Mac Addr
%odmc
Output Dst Mac Addr
%idmc
Input Dst Mac Addr
%osmc
Output Src Mac Addr
%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
%mpls
MPLS labels 1-10
%bps
bps - bits per second
%pps
pps - packets per second
%bpp
bps - Bytes per package
%sc
src IP 2 letter country code
%dc
dst IP 2 letter country code
%sloc
src IP geo location info
%dloc
dst IP geo location info
%sasn
src AS organisation name
%dasn
dst AS organisation name
%stor
src IP 2 letter tor exit info: TX tor exit node
%dtor
dst IP 2 letter tor exit info: TX tor exit node
%n
new line char \n
%ipl
input payload
%opl
output payload
%nbid
nbar ID
%ja3
ja3 hash
%sni
sni name in tls handshake
%nbnam
nbar name
%odid
observation domainID
%opid
observation pointID
OpenBSD pflog specific formats
%pfifn
pflog interface name
%pfact
pflog action
%pfrea
pflog reason
%pfdir
pflog direction
%pfrule
pflog rule nr
NSEL specific formats
%nfc
NSEL connection ID
%evt
NSEL event
%xevt
NSEL extended event
%sgt
NSEL Source security group tag
%msec
NSEL event time in msec
%iacl
NSEL ingress ACL
%eacl
NSEL egress ACL
%xsa
NSEL XLATE src IP address
%xda
NSEL XLATE dst IP address
%xsp
NSEL XLATE src port
%xdp
NSEL SLATE dst port
%xsap
Xlate Source Address:Port
%xdap
Xlate Destination Address:Port
%uname
NSEL user name
NEL/NAT specific formats
%nevt
NAT event - same as %evt
%ivrf
NAT ingress VRF ID
%evrf
NAT egress VRF ID
%nsa
NAT src IP address
%nda
NAT dst IP address
%nsp
NAT src port
%ndp
NAT dst port
%pbstart
NAT pool block start
%pbend
NAT pool block end
%pbstep
NAT pool block step
%pbsize
NAT pool block size
%flid
Flow ID
%isid
Nokia NAT in service ID
%osid
Nokia NAT out service ID
%nats
Nokia NAT string
Nprobe formats
%cl
Client latency
%sl
Server latency
%al
Application latency
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. Debian $Mdocdate$ NFDUMP (1)