Flexible Netflow Configuration
Jan 21, · Configuring NetFlow Data Export Using the Version 9 Export Format. Step 1. enable Example: Router> enable. Enters privileged EXEC mode. Enter your password if prompted. Step 2. configure terminal Example: Router# configure terminal. Enters global configuration mode. Step 3. . Cisco NetFlow Configuration Cisco IOS NetFlow Configuration Guide Netflow Configuration In configuration mode issue the following to enable NetFlow Export: ip flow-export destination ip flow-export source > (e.g. use File Size: 2MB.
This module contains information about and instructions for configuring NetFlow to capture and export network traffic data. NetFlow capture and export are performed independently on each internetworking device on which NetFlow is enabled. NetFlow need not be operational on each router in the network. NetFlow is emerging as a primary network accounting and security technology.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list configuge the releases in netflod each feature is supported, see the feature information table. Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www. An account on Cisco. Understand the resources required on your router because NetFlow consumes additional memory and CPU resources. NetFlow consumes additional memory. If you have memory constraints, you might want to preset the size of the NetFlow cache so that it contains a smaller number of entries.
The default cache size depends on the platform. Egress NetFlow accounting might adversely affect network performance because of the additional accounting-related computation that occurs in the traffic-forwarding path of the router.
Locally generated traffic traffic that is generated by the router on which the Egress NetFlow Accounting feature is configured is not counted as flow traffic for the Egress NetFlow Accounting feature. Backward compatibility--Version 9 is not backward-compatible with Version 5 or Version 8. Export bandwidth--Export bandwidth use increases for Version 9 because of template flowsets.
The increase in bandwidth usage versus Version 5 varies with the frequency with which template flowsets are how to configure netflow on cisco. The default is to resend templates every 20 packets, which has a bandwidth cost of about 4 percent. If necessary, you can lower the resend rate with the ip flow-export template refresh-rate packets command. Performance impact--Version 9 slightly decreases overall performance, because generating and maintaining valid template flowsets require additional processing.
NetFlow identifies packet flows for both ingress and egress IP packets. It does not involve any connection-setup protocol. NetFlow is completely transparent to the existing network, including end stations and application software and network devices like LAN switches. Also, NetFlow capture and export are performed independently on each internetworking device; NetFlow need not be operational on each router in the network. You can display and clear NetFlow statistics.
NetFlow statistics comfigure of IP packet size distribution, IP flow switching cache information, and flow information. A network flow is identified as a unidirectional stream of packets between a cisci source and destination--both are defined by a network-layer IP address and transport-layer source and destination port numbers. Specifically, a flow is identified as the combination of the following key fields:. These seven key fields define a unique flow.
If a packet has one key field that is different how to reduce pdf file size in adobe reader 8 another packet, it is considered to belong to another flow. A flow might contain other accounting fields such as the autonomous system number in the NetFlow export Version 5 flow format that depend on the export record version that you configure.
Flows are stored in the NetFlow cache. NetFlow operates by creating a NetFlow cache entry a flow record for each active flow. A flow record is maintained within the NetFlow cache for each active flows.
Each flow record in now NetFlow cache contains fields that can later be exported to a confgure device, such as the NetFlow Collection Engine. NetFlow is very efficient with the amount of export data being about 1.
NetFlow accounts for every packet non-sampled mode and provides a highly condensed and detailed view of all network traffic that entered the router or switch. The key to NetFlow-enabled switching scalability and performance is highly intelligent flow cache management, especially for densely populated and busy edge routers handling large numbers of concurrent, short duration flows. The NetFlow cache management software contains a highly sophisticated set of algorithms for efficiently determining if a packet is part of an existing flow or should generate a new flow cache entry.
Flows which have been idle for a specified time are expired and removed from the cache. Long-lived flows are expired and cnfigure from the cache. Flows are not allowed to live more than 30 minutes by default; the underlying packet conversation remains undisturbed.
As the cache becomes full, a number of heuristics are applied to aggressively age groups of flows simultaneously. Expired flows are grouped together into "NetFlow export" datagrams for export from the NetFlow- enabled device. The NetFlow functionality is configured on a per-interface basis. To configure NetFlow export capabilities, you need to specify the IP address and application port number of the Cisco NetFlow or third-party flow collector. The flow collector is a device that provides NetFlow export data filtering and aggregation capabilities.
The figure below shows an example of NetFlow data export from the main and aggregation caches to a collector. Version 9 is a flexible and extensible format, which how to get rid of mustache the versatility needed for support of new fields and record types.
The version 9 export format enables you to use the same version for how to configure netflow on cisco netfloww aggregation caches, and the format is extendable, so you can use the same export format with future features.
For all export versions, the NetFlow export datagram consists of a header and a sequence of flow records. The header contains information such as the sequence number, record count, and system uptime. The flow record contains flow information, for example, IP addresses, ports, and routing information. The distinguishing feature of the NetFlow Version how to configure netflow on cisco export format is that it is template based. Templates make the record format extensible.
This feature allows future enhancements to NetFlow without requiring concurrent changes to the basic flow-record format. The use of templates with the NetFlow Version 9 export format provides several other key benefits:.
This new information allows new applications for export data and new views of the network behavior. Third-party business partners who produce applications that provide collector or display services for NetFlow are not required to recompile their applications each time a new NetFlow hoow field is added. How to configure netflow on cisco, they might be able to use an external data netflos that documents the known template formats.
New features can be added to NetFlow more quickly, without breaking current implementations. In all five export versions, the configuure consists of a header and one or more flow records. The first field of the header contains the version number of the export datagram.
Typically, a receiving application that accepts any of the format versions allocates a buffer large enough for the largest possible datagram from any of the format versions, and then uses the header what does the bible say about spiritual fathers determine how to interpret the datagram.
The second field in the header contains the how to configure netflow on cisco of records in the datagram indicating the number of expired flows represented by this datagram.
Datagram headers for How to configure netflow on cisco Export Version 9 also includes a "sequence number" field used by NetFlow collectors to check for lost datagrams.
Incremental sequence counter of all export packets sent configurs this export device; this value is cumulative, and it can be used to find out whether any export packets have been missed.
The Source ID field is a bit value that is used to guarantee uniqueness for each flow exported from a particular device. The format of this field is vendor-specific. Byte 3 provides uniqueness with respect to the routing engine on the exporting device. Byte 4 provides uniqueness with respect to the particular line card or Versatile Interface Processor on the exporting device.
Collector devices should use the combination of the source IP address and the source ID field to associate an incoming NetFlow export packet with a unique instance of NetFlow on a particular device.
This section gives details about the Cisco export format flow record. The table below indicates which flow record format fields are available for Version 9. Y indicates that the field is available.
N indicates that the field is not available. The figure below shows a typical flow record contigure the Version 9 export how to configure netflow on cisco. The NetFlow Version 9 export record format is different from the traditional NetFlow fixed format export record.
In NetFlow Version 9, a template describes the NetFlow data and the flow set contains the actual data. This allows for flexible export. Detailed information about the fields currently in Version 9 and the export format architecture are confgure in the NetFlow Version 9 Flow-Record Format hoe.
For all export versions, you specify a destination where NetFlow data export packets are sent, such as the workstation running What makes you love someone so much Collection Engine, either when the number of recently expired flows reaches a predetermined maximum, or every second--whichever occurs first.
For detailed information on the flow record formats, data types, and export data fields for Version 9 and platform-specific information when applicable, see Appendix 2 in the NetFlow Solutions Service Guide.
The Version 9 export format supports export from the main cache and from aggregation caches. NetFlow Version 9 is a flexible and extensible means for transferring NetFlow records from a network node to a collector. NetFlow Version 9 has definable record types and is self-describing for easier NetFlow Collection Engine configuration.
You enable the features that you want, and the field values corresponding to those features are sent to the NetFlow Collection Engine. Third-party business partners, who produce applications that provide NetFlow Collection Engine or display services for NetFlow need not recompile their applications each time a new NetFlow technology is added.
Instead, with the NetFlow v9 Export Format feature, they can use an external data file that documents the known template formats and field types. Template descriptions are communicated from the router to the NetFlow Collection Engine.
Flow records are sent from the router to the NetFlow Collection Engine with minimal template information so that the NetFlow Collection Engine can relate the records to configur appropriate template. The main feature of the Cidco Version 9 export format is that it nftflow template based. A template describes a NetFlow record format and attributes of the fields such as type and length within the record.
The router assigns each template an ID, which is communicated to the NetFlow Collection Engine, along with the template description. The basic output of NetFlow is a flow record. In the NetFlow Version 9 export format, a flow record follows the same sequence of fields as found in the template definition. The template to which NetFlow flow records belong is determined by the prefixing of the template ID to the group of NetFlow flow records that belong to a template.
Finding Feature Information
Jan 25, · Ensure that one of the following is enabled on your router, and on the interfaces that you want to configure NetFlow on: Cisco Express Forwarding (CEF), distributed CEF, or fast switching. Understand the resources required on your router because . Jan 26, · Ensure that one of the following is enabled on your router, and on the interfaces that you want to configure NetFlow on: Cisco Express Forwarding (CEF), distributed CEF, or fast switching. Understand the resources required on your router because NetFlow consumes additional memory and CPU resources. Restrictions for Configuring NetFlow Top Talkers. Make sure your interface has a path to your NTA server. Next, add the port number. We will type transport UDP because that's the default port used by SolarWinds NetFlow Traffic Analyzer to listen for network packets. Next, add the flow protocol type and/or version: export-protocol netflow-v9.
Download the latest product versions and hotfixes. Manage your portal account and all your products. Get help, be heard by us and do your job better using our products. Get practical advice on managing IT infrastructure from up-and-coming industry voices and well-known tech leaders.
Depending on the Cisco device you are using, there may be additional steps required to successfully collect ingress and egress flow data.
However, in general, there are four basic steps to capturing flow data using Flexible NetFlow: create a flow record, create a flow exporter, create a flow monitor, and apply the flow monitor to interfaces. After you've logged into the router, go into global configuration mode by typing config t. Now create the flow record. For the purposes of this demo, we'll name it "NTA record," but you can use any name you like. Next, you'll define match and collect statements to capture fields to include in the flow record.
To collect both endpoints of the conversation, enter match ipv4 source address and then match ipv4 destination address. For application port data, type match transport source-port and match transport destination-port. If you're using Border Gateway Protocol or BGP in your environment, add the following commands to collect AS information: collect routing source as and collect routing destination as. Enter the command, flow exporter NTAExport. Again, you can name the exporter whatever you want.
So for this example, type destination Next, you'll need to identify the interface that's used to export NetFlow packets from the router. Next, add the port number. By default, the template is exported every 30 minutes. To process the data, the template needs to be available to prevent any gaps in data if the server reboots or the NetFlow service is restarted. You can avoid this problem by adding the command template data timeout 60 to set the template to export every minute.
Creating a flow monitor or NetFlow cache is pretty easy. We will call it NTAMonitor. To prevent gaps and spikes in your data, set the cache timeout values. This tells the router how frequently flow record information is exported to your analyzer tool. The default setting is 30 minutes.
If you use the default setting, your flow data will be delayed, and you will miss link saturation. To help ensure that the data is normalized and to avoid high peaks, set the cache timeout value to 60 seconds: cache timeout active To export all expired IP conversations, set cache timeout inactive to 15 seconds: cache timeout inactive The final step is to select the interfaces that will collect the NetFlow data.
Let's say we need to enable NetFlow on a gigabit Ethernet interface. And then, we'll use the command ip flow monitor NTAMonitor and add the key phrase input. This applies the monitor that we created to the interface and captures all incoming traffic for that interface. Remember, if your device is not configured properly, you can duplicate your data.
That's why it's important to understand the following rule:. When you collect NetFlow data on only one device interface and you want to display your data in both directions, set the following commands on the interface:. If you're collecting NetFlow data on multiple interfaces, enter only the input command line. Since each PDU contains the input and output interface, data will be collected in both directions even though you're only enabling the input command.
These configuration settings are important because flows can look the same to NTA even though the data is coming from different interfaces. To exit configuration mode, type exit and wr mem to save the configuration to the router. Now that you've configured NetFlow on your devices, you can start monitoring your network using NetFlow Traffic Analyzer and Network Performance Monitor to gain even more visibility into your network traffic. Developed by network and systems engineers who know what it takes to manage today's dynamic IT environments, SolarWinds has a deep connection to the IT community.
All Products. View All Network Management Products. Unify log management and infrastructure performance with SolarWinds Log Analyzer. View All Systems Management Products. Easy-to-use system and application change monitoring with Server Configuration Monitor.
View All Database Management Products. Monitor your cloud-native Azure SQL databases with a cloud-native monitoring solution. AppOptics SaaS-based infrastructure and application performance monitoring, tracing, and custom metrics for hybrid and cloud-custom applications.
Loggly Fast and powerful hosted aggregation, analytics and visualization of terabytes of machine data across hybrid applications, cloud applications, and infrastructure. Papertrail Real-time live tailing, searching, and troubleshooting for cloud applications and environments.
Pingdom Real user, and synthetic monitoring of web applications from outside the firewall. Web Performance Monitor Web application performance monitoring from inside the firewall. View All Application Management Products. N-able N-central Automate what you need. Tackle complex networks. Built to help maximize efficiency and scale. N-able Password Management Easily adopt and demonstrate best practice password and documentation management workflows. N-able Remote Support Help support customers and their devices with remote support tools designed to be fast and powerful.
Remote Monitoring. Renew Maintenance Learn about Auto-Renewal. Access the Success Center Find product guides, documentation, training, onboarding information, and support articles. Technical Support Submit a ticket for technical and product assistance, or get customer service help. Customer Portal Download the latest product versions and hotfixes.
Access the Customer Portal. Orange Matter Get practical advice on managing IT infrastructure from up-and-coming industry voices and well-known tech leaders. View Orange Matter. LogicalRead Blog Into databases? Find articles, code and a community of database experts. View LogicalRead Blog. View Resources. Contact Sales Online Quote.
Error Summary. First Name. Last Name. Business Email. Select State. Zip Code. Area Code. STD Code. Business Phone. I would like to receive SolarWinds promotional communications about products, services and events.
Product s featured in this video:. Enter flow record NTArecord. To collect protocol information, enter match ipv4 protocol. To collect type of service data, type match ipv4 tos. To collect the ingress interface data, enter match interface input.
<- What shots are needed to travel to africa - How to wirte a resume->