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diff --git a/docs/system/flow-accounting.rst b/docs/system/flow-accounting.rst new file mode 100644 index 00000000..4f566490 --- /dev/null +++ b/docs/system/flow-accounting.rst @@ -0,0 +1,146 @@ +.. _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 |