mirror of
https://github.com/opnsense/docs
synced 2024-11-15 06:12:58 +00:00
101 lines
3.2 KiB
ReStructuredText
101 lines
3.2 KiB
ReStructuredText
=========================
|
|
Netflow Export & Analyses
|
|
=========================
|
|
|
|
.. image:: images/netflow_analyzer_insight.png
|
|
:width: 100%
|
|
|
|
Netflow is a monitoring feature, invented by Cisco, it is implemented in the FreeBSD
|
|
kernel with ng_netflow (Netgraph). Since Netgraph is a kernel implementation it
|
|
is very fast with little overhead compared to softflowd or pfflowd.
|
|
|
|
While many monitoring solutions such as Nagios, Cacti and vnstat only capture traffic
|
|
statistics, Netflow captures complete packet flows including source, destination
|
|
IP and port number.
|
|
|
|
OPNsense offers full support for exporting Netflow data to external collectors as
|
|
well as a comprehensive Analyzer for on-the-box analysis and live monitoring.
|
|
|
|
OPNsense is the only open source solution with a built-in Netflow analyzer integrated
|
|
into its Graphical User Interface. It can be accessed via :menuselection:`Reporting --> Netflow`.
|
|
|
|
------------------
|
|
Supported Versions
|
|
------------------
|
|
OPNsense support both Netflow version 5 (IPv4) and version 9 (IPv4 & IPv6).
|
|
|
|
|
|
--------------
|
|
Netflow Basics
|
|
--------------
|
|
For analyzing the flow data it is important to understand the difference between
|
|
ingress and egress traffic.
|
|
|
|
Ingress
|
|
-------
|
|
Traffic to or coming from the firewall.
|
|
|
|
Egress
|
|
------
|
|
Traffic passing trough the firewall.
|
|
|
|
Ingress + Egress = Double flow count
|
|
------------------------------------
|
|
When enabling both ingress and egress, traffic gets counted double due to Network
|
|
Address Translation as all packets going to the WAN coming from the LAN pass the
|
|
Network translation of the firewall therefor also creating an ingress flow.
|
|
|
|
If you are not interested in ingress traffic then OPNsense offers the option to
|
|
filter this traffic. When utilizing a proxy on the same device its important to
|
|
capture the ingress flows as well, otherwise all proxy traffic won't be visible.
|
|
Downside is of course that all traffic not passing the proxy will we counted twice
|
|
due to the mentioned NAT effect.
|
|
|
|
----------------
|
|
Netflow Exporter
|
|
----------------
|
|
OPNsense Netflow Exporter supports multiple interfaces, filtering of ingress flows
|
|
and multiple destinations including local capture for analysis by Insight (OPNsense
|
|
Netflow Analyzer).
|
|
|
|
.. image:: images/netflow_exporter.png
|
|
:width: 100%
|
|
|
|
--------------------------
|
|
Netflow Analyzer - Insight
|
|
--------------------------
|
|
OPNsense offers a full Netflow Analyzer with the following features:
|
|
|
|
* Captures 5 detail levels
|
|
|
|
* Last 2 hours, 30 second average
|
|
* Last 8 hours, 5 minute average
|
|
* Last week, 1 hour average
|
|
* Last month, 24 hour average
|
|
* Last year, 24 hour average
|
|
|
|
* Graphical representation of flows (stacked, stream and expanded)
|
|
* Top usage per interface, both ips and ports.
|
|
* Full in/out traffic in packets and bytes
|
|
* Detailed view with date selection and port/ip filter (up to 2 months)
|
|
* Data export to csv for offline analysis
|
|
|
|
* Selectable Detail Level
|
|
* Selectable Resolution
|
|
* Selectable Dat range
|
|
|
|
.. image:: images/netflow_insight_details.png
|
|
|
|
-------------
|
|
Configuration
|
|
-------------
|
|
|
|
|
|
Setup Netflow Exporter
|
|
----------------------
|
|
See :doc:`/manual/how-tos/netflow_exporter`
|
|
|
|
Setup Insight
|
|
-------------
|
|
See :doc:`/manual/how-tos/insight`
|