mirror of
https://github.com/vyos/vyos-documentation.git
synced 2025-11-04 00:02:05 +01:00
147 lines
5.9 KiB
ReStructuredText
147 lines
5.9 KiB
ReStructuredText
.. _flow-accounting:
|
|
|
|
###############
|
|
Flow Accounting
|
|
###############
|
|
|
|
NetFlow is a feature that was introduced on Cisco routers around 1996 that
|
|
provides the ability to collect IP network traffic as it enters or exits an
|
|
interface. By analyzing the data provided by NetFlow, a network administrator
|
|
can determine things such as the source and destination of traffic, class of
|
|
service, and the causes of congestion. A typical flow monitoring setup (using
|
|
NetFlow) consists of three main components:
|
|
|
|
* **exporter**: aggregates packets into flows and exports flow records towards
|
|
one or more flow collectors
|
|
* **collector**: responsible for reception, storage and pre-processing of flow
|
|
data received from a flow exporter
|
|
* **application**: analyzes received flow data in the context of intrusion
|
|
detection or traffic profiling, for example
|
|
|
|
For connectionless protocols as like ICMP and UDP, a flow is considered complete
|
|
once no more packets for this flow appear after configurable timeout.
|
|
|
|
NetFlow is usually enabled on a per-interface basis to limit load on the router
|
|
components involved in NetFlow, or to limit the amount of NetFlow records
|
|
exported.
|
|
|
|
Configururation
|
|
===============
|
|
|
|
In order for flow accounting information to be collected and displayed for an
|
|
interface, the interface must be configured for flow accounting.
|
|
|
|
.. cfgcmd:: set system flow-accounting interface '<interface>'
|
|
|
|
Configure and enable collection of flow information for the interface
|
|
identified by `<interface>`.
|
|
|
|
You can configure multiple interfaces which whould participate in flow
|
|
accounting.
|
|
|
|
Flow Export
|
|
-----------
|
|
|
|
In addition to displaying flow accounting information locally, one can also
|
|
exported them to a collection server.
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow version '<version>'
|
|
|
|
There are multiple versions available for the NetFlo data. The `<version>`
|
|
used in the exported flow data can be configured here. The following
|
|
versions are supported:
|
|
|
|
* **5** - Most common version, but restricted to IPv4 flows only
|
|
* **9** - NetFlow version 9 (default)
|
|
* **10** - :abbr:`IPFIX (IP Flow Information Export)` as per :rfc:`3917`
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow server '<address>'
|
|
|
|
Configure address of NetFlow collector. NetFlow server at `<address>` can
|
|
be both listening on an IPv4 or IPv6 address.
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow source-ip '<address>'
|
|
|
|
IPv4 or IPv6 source address of NetFlow packets
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow engine-id '<id>'
|
|
|
|
NetFlow engine-id which will appear in NetFlow data. The range is 0 to 255.
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow sampling-rate '<rate>'
|
|
|
|
Use this command to configure the sampling rate for flow accounting. The
|
|
system samples one in every `<rate>` packets, where `<rate>` is the value
|
|
configured for the sampling-rate option. The advantage of sampling every n
|
|
packets, where n > 1, allows you to decrease the amount of processing
|
|
resources required for flow accounting. The disadvantage of not sampling
|
|
every packet is that the statistics produced are estimates of actual data
|
|
flows.
|
|
|
|
Per default every packet is sampled (that is, the sampling rate is 1).
|
|
|
|
.. cfgcmd:: set system flow-accounting netflow timeout expiry interval '<interval>'
|
|
|
|
Specifies the interval at which Netflow data will be sent to a collector. As
|
|
per default, Netflow data will be sent every 60 seconds.
|
|
|
|
|
|
Example:
|
|
--------
|
|
|
|
NetFlow v5 example:
|
|
|
|
.. code-block:: none
|
|
|
|
set system flow-accounting netflow engine-id 100
|
|
set system flow-accounting netflow version 5
|
|
set system flow-accounting netflow server 192.168.2.10 port 2055
|
|
|
|
Operation
|
|
=========
|
|
|
|
Once flow accounting is configured on an interfaces it provides the ability to
|
|
display captured network traffic information for all configured interfaces.
|
|
|
|
.. opcmd:: show flow-accounting interface '<interface>'
|
|
|
|
Show flow accounting information for given `<interface>`.
|
|
|
|
.. code-block:: none
|
|
|
|
vyos@vyos:~$ show flow-accounting interface eth0
|
|
flow-accounting for [eth0]
|
|
Src Addr Dst Addr Sport Dport Proto Packets Bytes Flows
|
|
0.0.0.0 192.0.2.50 811 811 udp 7733 591576 0
|
|
0.0.0.0 192.0.2.50 811 811 udp 7669 586558 1
|
|
192.0.2.200 192.0.2.51 56188 22 tcp 586 36504 1
|
|
192.0.2.99 192.0.2.51 61636 161 udp 46 6313 4
|
|
192.0.2.99 192.0.2.51 61638 161 udp 42 5364 9
|
|
192.0.2.99 192.0.2.51 61640 161 udp 42 5111 3
|
|
192.0.2.200 192.0.2.51 54702 22 tcp 86 4432 1
|
|
192.0.2.99 192.0.2.51 62509 161 udp 24 3540 1
|
|
192.0.2.99 192.0.2.51 0 0 icmp 49 2989 8
|
|
192.0.2.99 192.0.2.51 54667 161 udp 18 2658 1
|
|
192.0.2.99 192.0.2.51 54996 161 udp 18 2622 1
|
|
192.0.2.99 192.0.2.51 63708 161 udp 18 2622 1
|
|
192.0.2.99 192.0.2.51 62111 161 udp 18 2622 1
|
|
192.0.2.99 192.0.2.51 61646 161 udp 16 1977 4
|
|
192.0.2.99 192.0.2.51 56038 161 udp 10 1256 1
|
|
192.0.2.99 192.0.2.51 55570 161 udp 6 1146 1
|
|
192.0.2.99 192.0.2.51 54599 161 udp 6 1134 1
|
|
192.0.2.99 192.0.2.51 56304 161 udp 8 1029 1
|
|
|
|
|
|
.. opcmd:: show flow-accounting interface '<interface>' host '<address>'
|
|
|
|
Show flow accounting information for given `<interface>` for a specific host
|
|
only.
|
|
|
|
.. code-block:: none
|
|
|
|
vyos@vyos:~$ show flow-accounting interface eth0 host 192.0.2.200
|
|
flow-accounting for [eth0]
|
|
Src Addr Dst Addr Sport Dport Proto Packets Bytes Flows
|
|
192.0.2.200 192.0.2.51 56188 22 tcp 586 36504 1
|
|
192.0.2.200 192.0.2.51 54702 22 tcp 86 4432 1
|