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FlowViewer

flowviewer.net

Free plan WebLinux
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Spec score 8.1 #5 of 26 in Network Traffic Analysis Software

What it is

FlowViewer is free software for analyzing NetFlow data exported by an organization’s network devices. Its interface works with Carnegie Mellon’s SiLK software and also supports the older flow-tools collector. The toolset combines FlowViewer for text reports, FlowGrapher for charts, and FlowMonitor for longer-term traffic monitoring. It supports NetFlow versions 5 and 9, including IPv6, and offers filtering by address, port, interface, autonomous system, TOS, TCP flags, protocol, and next hop. More than 30 reports are available, and reports and filters can be saved. FlowGrapher charts bits, flows, and packets per second over a selected period; FlowMonitor provides RRD graphs for filtered traffic, with views from 24 hours to 3 years. Dashboards can give groups such as Security and Operations separate live views. FlowViewer is listed for Linux and web use and can be installed on a dedicated Unix server or virtual appliance; the software requires a Unix server. The free plan is free. Paid options include hourly support at a price agreed with the maker, router configuration at $500, paid once, training at $500, paid once, and installation at $750, paid once.

Spec sheet

Purpose
FlowViewer is free software for analyzing Netflow data exported from an organization's network devices.Read 8 Oct 2026 · flowviewer.net
Deployment
FlowViewer can be installed on a dedicated Unix server or virtual appliance.Read 8 Oct 2026 · flowviewer.net
Support
The maker offers installation, router Netflow configuration, training, and custom hourly support.Read 8 Oct 2026 · flowviewer.net
Architecture
It provides a dynamic user interface to Carnegie Mellon's SiLK software and also supports the legacy flow-tools collector.Read 8 Oct 2026 · flowviewer.net
Components
The toolset includes FlowViewer for text reports, FlowGrapher for graphical reports, and FlowMonitor for long-term traffic monitoring.Read 8 Oct 2026 · flowviewer.net
Contact
The contact page lists Joe Loiacono and an address in Ellicott City, Maryland.Read 8 Oct 2026 · flowviewer.net
Dashboards
Multiple dashboards let groups such as Security and Operations focus on their own concerns on a live operational basis.Read 8 Oct 2026 · flowviewer.net
Downloads
The downloads page lists FlowViewer tar files and user guides for versions 4.5 and 4.6.Read 8 Oct 2026 · flowviewer.net
Filtering
FlowViewer supports filtering by address, port, interface, autonomous system, TOS, TCP flags, protocol, and next hop.Read 8 Oct 2026 · flowviewer.net
Graphing
FlowGrapher graphs bits per second, flows per second, and packets per second over a specified time period.Read 8 Oct 2026 · flowviewer.net
Monitoring
FlowMonitor provides RRD graphs for filtered traffic, with views covering periods from 24 hours to 3 years.Read 8 Oct 2026 · flowviewer.net
Protocol support
The site says Netflow versions 5 and 9 are supported, including IPv6.Read 8 Oct 2026 · flowviewer.net
Reports
FlowViewer offers over 30 reports and lets users save reports and filters.Read 8 Oct 2026 · flowviewer.net

Plans and prices

FlowViewer Free Free software; requires a Unix server Read 8 Oct 2026 · flowviewer.net
Custom Support Priced on request per hour Minimum 4 hours Read 8 Oct 2026 · flowviewer.net
FlowViewer Training $500, paid once Training run-through; web conference using a live installation is suggested Read 8 Oct 2026 · flowviewer.net
Router Netflow Config $500, paid once Netflow configuration and troubleshooting until the stream reaches the collector Read 8 Oct 2026 · flowviewer.net
FlowViewer Install $750, paid once Full install of FlowViewer and SiLK on a Unix server Read 8 Oct 2026 · flowviewer.net

Every FlowViewer plan and price →

Strong points and limits

Strong points

  • Supports NetFlow versions 5 and 9, including IPv6.
  • Offers more than 30 reports and saved filters.
  • Graphs traffic rates and monitors filtered traffic over time.
  • Multiple dashboards can serve distinct operational groups.
  • The software plan costs nothing.

Limits

  • Requires a Unix server for the software.
  • Custom support costs what you agree with the maker, billed hourly.
  • Installation costs $750, paid once.

Who it suits

FlowViewer suits network teams that need to examine exported NetFlow data, create traffic reports, or monitor filtered traffic over time. Its dashboards can serve groups such as Security and Operations, while installation requires a Unix server.

Verdict

FlowViewer combines filtering, reporting, graphing, and longer-term traffic monitoring for NetFlow data. Its free software plan is clearly priced, but deployment requires a Unix server and paid setup or support services are listed separately.

Where Specifiction places it

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