FlowViewer

FlowViewer is a network-flow analysis suite for organizations that collect traffic data from their own network devices. It is best suited to teams that can run a Unix server and want reporting, graphs, and ongoing monitoring in one package. Its breadth comes at no software cost, while deployment depends on Unix infrastructure.

Overview

FlowViewer provides a dynamic interface to Carnegie Mellon’s SiLK software and also supports the legacy flow-tools collector. Its three components serve different jobs: FlowViewer produces text reports, FlowGrapher visualizes traffic rates, and FlowMonitor tracks filtered traffic over time. Together, they give network teams a way to investigate traffic and keep operational views in one toolset.

NetFlow versions 5 and 9 are supported, including IPv6; the protocol list also includes IPFIX and sFlow. Teams should make sure their collector and device workflow fits before settling on FlowViewer. Deployment requires a dedicated Unix server or virtual appliance, so it is a poor fit for organizations looking for a hosted service or software that avoids server administration.

Key features

Reports and filters

More than 30 reports and the ability to save reports and filters help analysts return to recurring investigations without rebuilding each view. Filters cover address, port, interface, autonomous system, TOS, TCP flags, protocol, and next hop. That range supports focused traffic analysis across several common network dimensions.

Graphs and monitoring

FlowGrapher plots bits, flows, and packets per second over a chosen period, making it useful for examining how traffic rates change. FlowMonitor supplies RRD graphs for filtered traffic, with views spanning 24 hours to three years. That long range gives operations teams a way to keep an eye on traffic patterns over time, while the multiple dashboards let groups such as Security and Operations concentrate on their own concerns during live operations.

Pricing

The FlowViewer software costs nothing. That makes it an option for teams willing to operate the required Unix server and handle deployment themselves. Paid services are available for organizations that need help getting the system running or training users:

• Custom Support: from $75 (priced on request), billed per hour, with a 4-hour minimum. This fits teams that need targeted help with setup or use.
• Router Netflow Config: $500, paid once for configuration and troubleshooting until the stream reaches the collector. It suits teams that need help establishing the data feed.
• FlowViewer Training: $500, paid once for a training run-through; a web conference using a live installation is suggested. This is aimed at teams that want guided instruction.
• FlowViewer Install: $750, paid once for a full FlowViewer and SiLK installation on a Unix server. It is the most direct option for organizations that want installation handled for them.

Platforms

FlowViewer is listed for Linux and the web. It can be installed on a dedicated Unix server or virtual appliance, so organizations need to provide server infrastructure as part of adopting it.

Who it's for

FlowViewer is a good match for network and security teams that already collect flow data, can operate a Unix server, and want reports, rate graphs, and longer-term filtered monitoring together. Its saved filters and multiple dashboards are useful when people revisit recurring questions or different teams need separate operational views. Teams that need installation or router configuration help can buy those services.

It is less suitable for organizations that want a managed hosted product or do not have Unix server capacity. Teams should also confirm that the flow formats and collector support align with their environment before choosing it.

Pros and cons

• Pro: The software is free, while reports, graphing, and monitoring are combined in one suite.
• Pro: More than 30 reports, saved filters, and filters across addresses, ports, interfaces, and other network fields support repeatable investigations.
• Pro: FlowMonitor offers filtered traffic views from 24 hours to three years, useful for both recent operations and longer-term review.
• Con: Installation requires a Unix server, which adds infrastructure and administration work.
• Con: Teams wanting guided deployment, router configuration, or training must budget for paid services.
• Con: The stated NetFlow support centers on versions 5 and 9, so organizations should confirm their data workflow is compatible.

Alternatives

ntopng is worth considering for practitioners who want a freemium product with a broader range of listed platforms, including Windows and macOS; its free Community plan is designed for small networks, with a suggested maximum of 256 live local hosts.

ManageEngine NetFlow Analyzer may fit teams that need mobile access or a paid edition with a defined interface allowance: its free edition covers 2 interfaces, while Standard is $172 a month for 10 interfaces.

Nagios XI is another option for teams comparing monitoring software with a free tier capped at 7 nodes or 100 services, whichever comes first, and a paid Standard edition.

Caligare Flow Inspector offers a free edition for non-commercial use, limited to 2 devices, 24-hour history, and 250 flows per second.

ElastiFlow may suit teams looking for a free tier with stated record-rate and SNMP-device caps, dashboards, detections, and community support.

Riverbed Aternity is an enterprise offering with custom pricing.

nfdump is a free, BSD-licensed Linux and self-hosted alternative.

Akvorado is a free alternative developed by Free, a French ISP.

Browse more options in Network Traffic Analysis Software and Bandwidth Monitoring Software.

Verdict

Choose FlowViewer if your organization already collects flow data, can run a Unix server, and wants text reports, traffic graphs, and long-term filtered monitoring without a software license cost. Its breadth and saved views make it a practical fit for teams with recurring analysis and operational needs. Look elsewhere if server administration is a poor fit or your collector workflow does not align with its supported flow formats.