Network Traffic Monitoring: 9 Best Bandwidth Monitoring Tools for 2026

Network traffic monitoring means measuring how much data crosses each link and working out which hosts, applications and conversations are responsible. Bandwidth monitoring tools do the first half by reading interface counters over SNMP. Traffic analysers do the second half by collecting flow records (NetFlow, sFlow, IPFIX) or capturing packets. For most business networks, the right setup is SNMP for utilisation, flow data for “who is using it”, and a packet analyser such as Wireshark on standby for deep troubleshooting.

Quick picks, with vendor-published pricing checked September 2026:

Best all-rounder for SMBs: PRTG Network Monitor (free up to 100 sensors; paid from $200 per month, billed annually).
Best free traffic analyser: ntopng Community (GPLv3, free).
Best for packet-level troubleshooting: Wireshark (free, open source).
Best NetFlow analyser for Windows shops: ManageEngine NetFlow Analyzer.
Best for large, multi-cloud or ISP networks: Kentik.
Best cloud-native option: Datadog NetFlow Monitoring (priced per million flow records).

What is traffic monitoring in networking?

Traffic monitoring answers three questions: how full are my links, what is filling them, and is any of it abnormal? It sits alongside availability monitoring (is the device up?) as one part of broader network monitoring. Teams use it to find bandwidth hogs, size WAN and internet circuits, prove or disprove “the network is slow” complaints, spot data exfiltration or malware beaconing, and allocate costs between departments or customers.

Is there a way to monitor network traffic?

Yes, and there are three technical approaches. Most tools below use one or two of them.

Approach	How it works	Answers	Blind spot
SNMP interface counters	Poll byte counters on each router or switch port every 1 to 5 minutes	How full is each link?	Cannot say which host or app is responsible
Flow analysis (NetFlow v9, IPFIX, sFlow, J-Flow)	Routers and firewalls export a summary of each conversation to a collector	Who is talking to whom, on which port, and how much?	No payload; sampled flows (sFlow) are estimates
Packet capture	Copy packets from a SPAN port or TAP and decode them	Exactly what happened, byte by byte	Storage-heavy; hard to run continuously

A practical rule: turn on SNMP everywhere, export flows from the internet edge and WAN routers, and capture packets only when flow data points you at a specific problem.

Network traffic and bandwidth monitoring tools compared

Tool	Data sources	Deployment	Free option	Paid pricing (vendor-published, checked September 2026)
PRTG Network Monitor	SNMP, NetFlow v9 and other sensors	Self-hosted (Windows)	Freeware up to 100 sensors	From $200/month billed annually (500 sensors)
ntopng	NetFlow, sFlow, IPFIX (with nProbe), packet capture	Self-hosted (Linux and others)	Community edition, GPLv3	Perpetual licences from €299.95 (Pro), shown in EUR
Wireshark	Packet capture	Desktop	Free, GPLv2	None
SolarWinds NetFlow Traffic Analyzer	NetFlow and other flow formats	Self-hosted	30-day trial	Quote-only standalone; flow analysis in Observability Self-Hosted Advanced from $14/node/month (multi-year, billed annually)
ManageEngine NetFlow Analyzer	NetFlow, sFlow, IPFIX and more	Self-hosted	Free for 2 interfaces; 30-day trial	From US$245/year (Professional, 10 interfaces)
Kentik	NetFlow, sFlow, IPFIX, cloud flow logs, SNMP	SaaS	30-day trial	Pro from $2,000/month billed annually
Datadog NetFlow Monitoring	NetFlow v5/v9, IPFIX, sFlow, jFlow	SaaS	14-day trial	From $0.60 per million flow records/month (15-day retention, annual)
WhatsUp Gold (NTA+)	SNMP, NetFlow, IPFIX, sFlow, J-Flow	Self-hosted (Windows)	Free edition, 10 devices	From $1,229/year for 50 devices (Business)
Nagios Network Analyzer	NetFlow, sFlow, J-Flow, IPFIX	Self-hosted	30-day trial	$4,995 single licence

The best network traffic monitoring tools in 2026

1. PRTG Network Monitor: best all-rounder for small and mid-size networks

Paessler PRTG combines bandwidth monitoring and traffic analysis in one Windows install. Its SNMP Traffic sensor graphs utilisation on every switch and router port, and its NetFlow v9 sensor breaks traffic down by type, so one tool answers both “how full” and “what is using it”. Licensing counts sensors; each monitored port or flow source uses one.

Pricing (vendor-published, checked September 2026): PRTG 500 is $200/month, PRTG 1000 is $358/month and PRTG 2500 is $742/month, paid annually. Subscription only.
Free: Freeware Edition up to 100 sensors (about 10 devices); 30-day trial with unlimited sensors.
Best for: teams that want graphs and alerts working the same day without stitching tools together.

2. ntopng: best free traffic analyser

ntopng, from ntop, is a web-based traffic analyser that shows top hosts, applications and flows in real time, either by inspecting packets on an interface or by collecting NetFlow, sFlow and IPFIX exports (flow collection uses ntop’s companion nProbe). It also integrates with Checkmk. The Community edition is free under GPLv3.

Pricing (vendor-published, checked September 2026): paid licences are perpetual and include a year of maintenance. The ntop shop lists them in euros: Pro €299.95, Enterprise M €699.95, Enterprise L €899.95, Enterprise XL €1,499.95.
Best for: Linux-comfortable teams that want real-time application visibility on a budget.

3. Wireshark: best for packet-level troubleshooting

Wireshark is the standard free packet analyser. It captures and decodes traffic on the interface it runs on (or from a mirror port or TAP), with filters for hundreds of protocols. It is not a 24/7 monitor, but when flow data points to a problem host, Wireshark shows exactly what that host is sending. The current stable release is 4.6.9, licensed under GPLv2.

Pricing: free; Wireshark’s FAQ says the free download “is the full version”.
Best for: root-cause analysis of retransmissions, slow applications and odd protocol behaviour.

4. SolarWinds NetFlow Traffic Analyzer: best for existing SolarWinds shops

SolarWinds NTA collects flow data and shows top talkers, applications and conversations alongside the SNMP data in SolarWinds NPM. SolarWinds now positions NTA as a feature of SolarWinds Observability Self-Hosted (formerly Hybrid Cloud Observability), where flow monitoring and analysis is included from the Advanced tier.

Pricing (vendor-published, checked September 2026): standalone NTA is quote-only. Observability Self-Hosted Advanced starts at $14 per node per month on multi-year contracts billed annually.
Free: 30-day fully functional trial.
Best for: enterprises already running SolarWinds that want flows in the same console.

5. ManageEngine NetFlow Analyzer: best value flow analyser for Windows teams

NetFlow Analyzer is an on-premises tool licensed per interface that collects NetFlow, sFlow, IPFIX and other flow formats, with bandwidth reports, application breakdowns and alerts. It also plugs into ManageEngine OpManager as an add-on.

Pricing (vendor-published, checked September 2026): the ManageEngine store lists Professional at US$245 per year for 10 interfaces, US$595 for 25 and US$1,145 for 50; Enterprise starts at US$445 for 10 interfaces. (ManageEngine’s editions page shows different “starting” figures, so confirm in the store before buying.)
Free: free forever for 2 interfaces; 30-day trial.
Best for: mid-size networks that want flow reporting without SaaS or large contracts.

6. Kentik: best for large, multi-cloud and service provider networks

Kentik is a SaaS network observability platform built around flow data. It ingests NetFlow, sFlow, IPFIX and cloud flow logs, enriches them with BGP, geography and device context, and adds SNMP device monitoring and synthetic tests. Infoblox completed its acquisition of Kentik in August 2026; Kentik continues under its own brand.

Pricing (vendor-published, checked September 2026): Pro starts at $2,000 per month, billed annually ($24,000 a year), with 1,000 flows per second and 25 NMS devices included. Premier is quote-only. Annual contracts only.
Free: 30-day trial.
Best for: ISPs, content providers and large enterprises with heavy internet edge or multi-cloud traffic.

7. Datadog NetFlow Monitoring: best for teams already on Datadog

Datadog’s NetFlow Monitoring accepts NetFlow v5 and v9, IPFIX, sFlow and jFlow and sits alongside its Network Device Monitoring (SNMP) and Cloud Network Monitoring products, so traffic, device and application data share one platform.

Pricing (vendor-published, checked September 2026): $0.60 per million aggregated flow records per month with 15-day retention, rising to $0.85 for 90-day retention (billed annually). Network Device Monitoring is $7 per device per month billed annually.
Free: 14-day trial of the full suite.
Best for: cloud-first teams; model your flow volume first, because pricing scales with records.

8. WhatsUp Gold with NTA+: best on-premises all-in-one for Windows shops

Progress WhatsUp Gold monitors devices over SNMP v1 to v3, WMI and SSH, and its Network Traffic Analysis Plus (NTA+) collector stores NetFlow, IPFIX, sFlow and J-Flow data for bandwidth and top-talker reports, next to its topology maps.

Pricing (vendor-published, checked September 2026): per year for 50 devices: Business from $1,229, Enterprise from $2,049, Enterprise Plus from $3,469. Confirm which edition includes NTA+ when you request a quote.
Free: Free Edition for up to 10 devices.
Best for: Windows-centric IT teams that want one on-premises console.

9. Nagios Network Analyzer: best add-on for Nagios users

Nagios Network Analyzer collects NetFlow, sFlow, J-Flow and IPFIX and presents bandwidth and top-talker views for teams that already monitor devices with Nagios XI.

Pricing (vendor-published, checked September 2026): a single $4,995 licence with no user limit.
Free: 30-day trial.
Best for: existing Nagios environments.

If device health and SNMP polling matter more to you than traffic breakdowns, see our guide to SNMP monitoring tools.

Is there a free tool for monitoring bandwidth?

Several, depending on scope:

Whole network, SNMP-based: PRTG Freeware (up to 100 sensors), Cacti (GPL, graphs SNMP counters with RRDtool), LibreNMS and Zabbix.
Whole network, flow-based: ntopng Community. ManageEngine NetFlow Analyzer is free for 2 interfaces.
Single computer: Sniffnet (free, MIT or Apache-2.0, runs on Windows, macOS and Linux) and Windows’ built-in Resource Monitor.
Packet analysis: Wireshark.

For a wider view of free options, including ones that handle availability and alerting, see our guide to the best network monitoring software.

How do I monitor my bandwidth usage?

Pick the choke points. Internet edge, WAN links between sites, uplinks from access switches, and links to key servers or storage.
Enable SNMP (preferably v3) on those devices and add them to your monitoring tool. Use the 64-bit counters (ifHCInOctets and ifHCOutOctets) on gigabit and faster links so the counters do not wrap between polls.
Export flows (NetFlow v9 or IPFIX, or sFlow on switches) from the edge router or firewall to your collector.
Baseline for two weeks before setting alerts, so you know what a normal Monday morning looks like.
Alert on sustained utilisation (for example, above 80% for 15 minutes), not single spikes.
Review the 95th percentile monthly. Many carriers bill burstable circuits on it, and it is the right number for capacity planning.

What is killing my bandwidth?

Flow data usually answers this in minutes. The usual suspects on business networks are cloud backup and file sync jobs running during the day, OS and application updates hitting many machines at once, video calls and streaming, large file transfers to or from SaaS storage, and, less often, a compromised host sending data out. Sort your flow tool’s “top talkers” and “top applications” views by bytes for the busy period, then check whether the traffic is expected. Scheduling backups and updates outside business hours and applying QoS to voice and video fixes most cases.

How do you tell if someone is monitoring your internet traffic?

On a company network, assume traffic metadata is monitored; flow logs and firewall logs are standard, and acceptable-use policies normally disclose it. Signs of monitoring you did not authorise include switch ports configured to mirror traffic without a change record, unknown flow export destinations in router configs, unfamiliar devices on the network, and unexpected root certificates installed on endpoints (a sign of TLS interception). Comparing device configurations against a known-good backup and keeping an up-to-date network diagram make these easier to catch.

How to choose a network traffic monitoring tool

Small office, one site: PRTG Freeware or Paessler’s paid tiers for SNMP bandwidth, plus Wireshark for troubleshooting.
Mid-size, several sites, mostly Windows admins: ManageEngine NetFlow Analyzer or SolarWinds NTA alongside an SNMP monitor.
Linux-comfortable team on a budget: ntopng with LibreNMS or Zabbix.
Cloud-heavy or already on Datadog: Datadog NetFlow and Network Device Monitoring.
Service provider, large enterprise or multi-cloud: Kentik.

Before buying, check three things in a trial: which flow versions your routers export (and whether the tool accepts them), how long raw flow data is retained, and whether per-device or per-flow pricing will balloon as you add sites. The network monitoring software category lists more tools.

Frequently asked questions

Which tool is commonly used to monitor network traffic?

Wireshark is the most widely used packet analyser and is free. For continuous, network-wide traffic monitoring, teams typically use a flow analyser such as ntopng, PRTG, ManageEngine NetFlow Analyzer or SolarWinds NTA.

What is the difference between bandwidth monitoring and traffic analysis?

Bandwidth monitoring measures how full a link is, usually from SNMP counters. Traffic analysis explains what is filling it, using flow records or packet captures. You need both to fix a congested link.

Do I need NetFlow, or is SNMP enough?

SNMP is enough to know a link is saturated and to plan capacity. Add NetFlow, IPFIX or sFlow when you need to name the host or application responsible, or when security teams want conversation records.

Can Wireshark monitor a whole network?

Only the traffic that reaches the interface it captures on. To see more, connect it to a switch mirror (SPAN) port or a network TAP. It is a troubleshooting tool, not a 24/7 monitor.

What is a good tool to test network bandwidth?

Monitoring tools measure the traffic you already have. To test a link’s capacity, use a throughput test such as iperf3 between two hosts, or a synthetic monitoring tool that runs scheduled speed and latency tests between sites.

How long should flow data be kept?

Thirty to ninety days of detailed flows covers most troubleshooting and security investigations; keep aggregated summaries longer for capacity trends. Check what your tool’s plan includes, because retention often drives price.