Connection events
A connection event is a log that records connections that your managed devices monitor. It includes Security-Related connection events. These are connections that the reputation-based Security Intelligence feature blocks. It also provides granular control over which connections to log, when to log them, and where to store the data.
Connection event detection sources
Connection events generally include transactions detected by:
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Access control policies
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Decryption policies
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Prefilter policies (captured by prefilter or tunnel rules)
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DNS Block lists
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URL Block lists
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Network (IP address) Block lists
Settings in rules and policies give you granular control over which connections you log, when you log them, and where you store the data.
For more information, refer to Connection Logging.
Connection vs. security-related connection events
A Security-Related connection event is a connection event that
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is generated whenever a session is blocked or monitored by the reputation-based Security Intelligence feature, and
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has an identical corresponding connection event that can be viewed and analyzed independently.
Event processing and storage
The system creates an identical connection event for every Security-Related connection event. You can view and analyze Security-Related connection events independently. The system stores and prunes these events separately.
The system enforces Security Intelligence before more resource-intensive evaluations. When Security Intelligence blocks a connection, the resulting event lacks information from subsequent evaluations, such as user identity.
Note |
In this guide, information about connection events also pertains to Security-Related connection events, unless otherwise noted. |
NetFlow connections
NetFlow connections are unidirectional end-of-connection events that
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supplement connection data gathered by managed devices,
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are generated from records broadcast by NetFlow exporters, and
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are logged in the Secure Firewall Management Center database.
NetFlow connection characteristics
The system logs NetFlow records as unidirectional end-of-connection events in the Secure Firewall Management Center database. The available information for these connections differs somewhat from connections detected by your access control policy. For more information, refer to Differences between NetFlow and managed device data.
Connection summaries (aggregated data for graphs)
Connection summaries are collections of aggregated data that
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aggregate connection data over 5-minute intervals,
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generate connection graphs and traffic profiles, and
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support custom workflows based on connection summary data.
The system aggregates connection data collected over five-minute intervals into connection summaries, which the system uses to generate connection graphs and traffic profiles. Optionally, you can create custom workflows based on connection summary data, which you use in the same way as you use workflows based on individual connection events.
To be aggregated, multiple connections must:
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represent the end of connections
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have the same source and destination IP addresses, and use the same port on the responder (destination) host
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use the same protocol (TCP or UDP)
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use the same application protocol
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either be detected by the same managed device or by the same NetFlow exporter
Each connection summary includes total traffic statistics, as well as the number of connections in the summary. NetFlow exporters generate unidirectional connections. The system increments a summary's connection count by 2 for every NetFlow-based connection.
There are no connection summaries specifically for Security-Related connection events, although the system can aggregate corresponding end-of-connection events into connection summary data.
Note |
Connection summaries do not contain all information associated with their aggregated connections. For example, because client information is not used to aggregate connections into connection summaries, summaries do not contain client information. |
Long-running connections
A long-running connection is a monitored session that
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spans two or more five-minute intervals during which the system aggregates connection data,
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increases the connection count only when the session starts, and
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uses estimated calculations based on constant rates rather than actual data for each interval.
Connection counting and traffic calculation behavior
When the system calculates the number of packets and bytes for long-running connections, it does not report actual transmission data for each five-minute interval. Instead, it uses a constant transmission rate and calculates estimates based on the total number of packets and bytes transmitted, connection length, and the connection portion in each interval.
Combined connection summaries from external responders
A combined connection summary is a data optimization technique that
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reduces connection data storage space by aggregating summaries when one host is not on the monitored network,
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improves connection graph rendering performance by combining connections that meet summary aggregation criteria, and
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displays
externalinstead of an IP address for non-monitored hosts in connection summaries and graphs.
Aggregation criteria and display behavior
To reduce the space required to store connection data and speed up the rendering of connection graphs, the system combines connection summaries when:
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one of the hosts involved in the connection is not on your monitored network
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except for the IP address of the external host, the connections in the summaries meet the summary aggregation criteria
When viewing connection summaries in the submenu pages, and when working with connection graphs, the system displays external instead of an IP address for the non-monitored hosts.
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As a consequence of this aggregation, if you attempt to drill down to the table view of connection data (that is, access data on individual connections) from a connection summary or graph that involves an external responder, the table view contains no information. |


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