Flowtriq vs FastNetMon:
DDoS detection compared

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Why This Comparison Matters

FastNetMon and Flowtriq are both built to detect DDoS attacks, but they approach the problem from opposite directions. FastNetMon sits at the network infrastructure layer, ingesting flow telemetry from routers and switches. Flowtriq runs as a lightweight agent on each server, monitoring traffic directly at the host. This architectural difference cascades into every aspect of how each product works — what it detects, how fast it detects, what data it gives you, and how it responds.

FastNetMon has been a staple in the service provider and hosting world since 2014. It ships in two editions: FastNetMon Community (open source, free) and FastNetMon Advanced (commercial, quote-based pricing). The Community edition is a capable starting point for basic threshold-based detection, but the feature gap between Community and Advanced is substantial. Most production deployments that outgrow Community end up on Advanced or looking for alternatives.

Flowtriq is a SaaS platform purpose-built for DDoS detection, classification, and forensics. It runs a per-server agent that monitors traffic at one-second granularity, classifies attacks across eight families with confidence scoring, captures PCAP with a pre-attack buffer, and pushes alerts through seven notification channels. It is priced at $9.99 per node per month.

This is not a marketing piece that pretends one product is universally better. Both tools have legitimate use cases. The goal here is to lay out what each product actually does, where each one excels, and help you choose the right tool — or combination of tools — for your environment.

How FastNetMon Works

FastNetMon is a flow collector and analyzer. It receives NetFlow v5/v9, sFlow, IPFIX, or mirrored traffic from your network equipment — routers, switches, or span ports — and applies threshold-based rules to detect volumetric anomalies. When traffic to a particular destination IP exceeds configured thresholds (typically in packets per second, bits per second, or flows per second), FastNetMon triggers an action.

The primary response mechanism in FastNetMon is BGP-based. When an attack is detected, FastNetMon announces a BGP blackhole route for the targeted IP through an ExaBGP or GoBGP session with your upstream routers. This triggers Remote Triggered Black Hole (RTBH) filtering, which instructs upstream routers to drop all traffic destined for the attacked IP before it enters your network. Effective at stopping the flood, but the collateral damage is total: the protected IP becomes unreachable to legitimate traffic as well.

FastNetMon Community provides basic threshold detection, syslog alerting, and BGP blackhole triggering. It has no web dashboard, no API, no attack classification beyond the protocol level, and limited notification options. Configuration is done through a command-line tool or config files. For a free, open-source tool, it does a credible job at the core use case: detecting large volumetric attacks and triggering automated blackhole responses.

FastNetMon Advanced extends Community with a web UI, REST API, per-host bandwidth graphs, additional flow protocol support, email and Slack notifications, traffic accounting, and more granular threshold configuration. It is a significant upgrade over Community, particularly for organizations that need operational visibility beyond command-line output.

The Sampling Problem

The fundamental constraint of any flow-based detection system is sampling. NetFlow and sFlow do not capture every packet. They sample at configurable ratios — commonly 1:1000, 1:2000, or even 1:4096 on high-throughput interfaces. This means FastNetMon sees a statistical representation of your traffic, not the actual traffic itself.

At high traffic volumes, sampling produces reasonable accuracy for aggregate metrics. At lower volumes or for short-duration attacks, sampling introduces significant blind spots. A 30-second attack at 50,000 PPS on an interface sampled at 1:1000 produces approximately 50 sampled flow records per second — enough for basic threshold detection but not enough for source IP analysis or attack characterization. A 10-second attack may not generate enough flow records to cross any threshold before it ends.

Flow sampling is not a flaw — it is an engineering tradeoff. Routers cannot export full packet data at line rate. Sampling is what makes flow-based monitoring scalable to 100 Gbps+ interfaces. The tradeoff is detection granularity, and for service providers monitoring aggregate backbone traffic, it is the right tradeoff. For individual server protection, the calculus is different.

How Flowtriq Works

Flowtriq takes the opposite approach. Instead of collecting flow data from network infrastructure, Flowtriq runs a lightweight agent on each server that monitors the network interfaces directly. The agent inspects every packet header (not sampled — every one), builds per-second traffic profiles, maintains a rolling baseline of normal traffic patterns, and detects anomalies against that baseline.

Because the agent sees all traffic at the host level, it has access to information that flow telemetry does not provide: exact source and destination ports, full protocol breakdown, packet size distributions, TCP flag combinations, and the actual packet data itself. This enables Flowtriq to classify attacks into eight distinct families — UDP flood, SYN flood, DNS amplification, NTP amplification, ICMP flood, HTTP flood, TCP ACK flood, and multi-vector — with a confidence score for each classification.

Detection latency is one second. The agent evaluates traffic every second against the dynamic baseline and triggers an alert the moment an anomaly exceeds the detection threshold. Alerts are pushed through your configured notification channels — Discord, Slack, email, PagerDuty, OpsGenie, SMS, or custom webhooks — within seconds of attack onset. There is no polling interval, no flow export delay, and no sampling gap to bridge.

For forensics, Flowtriq maintains a rolling PCAP buffer that captures the last N seconds of traffic. When an attack is detected, the buffer is flushed to disk and attached to the incident record. This gives you actual packet data from before the attack started — not sampled flows, not metadata, but real packets that you can open in Wireshark or submit to your upstream provider as evidence for mitigation requests.

Detection Capabilities Compared

The differences in detection capability stem directly from the architectural difference between flow sampling and per-packet monitoring.

Attack Classification

FastNetMon (both editions) does not classify attacks by type. It detects threshold violations on aggregate metrics — total PPS, total BPS, or total flow count to a destination IP. It knows that traffic has spiked, but it does not tell you whether the spike is a SYN flood, a DNS amplification attack, or a UDP reflection. The Community edition provides the raw protocol distribution in its console output, which an experienced operator can use to infer the attack type. Advanced adds some protocol-level breakdown in its dashboard. But neither edition provides automated attack classification with confidence scoring.

Flowtriq classifies every detected incident into one of eight attack families with a confidence percentage. A typical incident record might show: "UDP Flood (confidence 94%), secondary vector SYN Flood (confidence 23%)." This classification drives downstream behavior — different alert templates, different firewall rules, and different forensic analysis for each attack type. For multi-vector attacks, Flowtriq identifies each component separately.

Detection Latency

FastNetMon's detection latency depends on the flow export interval of your network equipment. Most routers export flow records in batches at configurable intervals — typically every 10, 30, or 60 seconds. Even with aggressive export intervals (every 5 seconds) and FastNetMon's own processing time, realistic detection latency ranges from 10 to 60 seconds. For attacks shorter than the flow export interval, detection may not happen at all.

Flowtriq detects at one-second granularity. The agent evaluates traffic every second, and alerts fire within one to two seconds of the anomaly exceeding the threshold. For short-duration attacks (10-30 seconds), this difference is the difference between detecting the attack and missing it entirely.

Source Analysis

Flow data includes source IP addresses, but at sampling ratios of 1:1000+, the source IP distribution in flow records is a statistical estimate, not a census. FastNetMon can show you approximate top talkers based on sampled data, but the accuracy degrades as sampling ratios increase and attack durations decrease.

Flowtriq sees every packet and provides exact source IP distributions, source AS numbers, source country breakdown, and a source diversity score. When you need to file an abuse report or request upstream filtering for specific source ranges, exact source data matters.

Same Attack, Different Data: A Side-by-Side Scenario

To make the differences concrete, consider a real-world scenario: a 40-second DNS amplification attack at 350,000 PPS targeting a game server on port 27015. The attack uses approximately 12,000 unique source IPs spoofed across 80+ ASNs, with an average amplified response size of 512 bytes. Here is what each product gives you.

Mitigation: Blackhole vs 22 Action Types

FastNetMon's mitigation story is fundamentally about BGP. When an attack is detected, FastNetMon announces a blackhole route, and upstream routers drop all traffic to the targeted IP. This is effective at stopping the flood, but it is a binary response: the target is either fully online or fully offline. There is no middle ground, no selective filtering, and no way to keep legitimate traffic flowing while blocking attack traffic.

FastNetMon Advanced supports additional actions beyond blackhole — it can trigger external scripts, call webhooks, or push to Flowspec for more granular BGP-based filtering (if your upstream supports it). Flowspec support is a meaningful upgrade, as it allows filtering by protocol, port, and packet size rather than blackholing the entire IP. However, Flowspec adoption is still limited among many transit providers and hosting networks.

Flowtriq's firewall rules system supports 22 distinct action types that can be combined in rules triggered by attack classification, severity, target port, or other incident attributes. Actions include rate limiting by source, protocol, or port; iptables/nftables rule insertion; traffic shaping; webhook callbacks to orchestration systems; API calls to upstream providers that support programmatic filtering; and more. Because Flowtriq knows what type of attack is occurring, it can apply targeted mitigation — rate-limit UDP to port 27015 during a DNS amplification attack while leaving TCP traffic untouched, for example.

The practical difference: during a DDoS attack, FastNetMon's blackhole takes the server offline entirely. Flowtriq's targeted mitigation can keep the server online and serving legitimate traffic while the attack is in progress. For services where availability matters (which is most services), this is a significant operational advantage.

Alerting and Notification

FastNetMon Community's alerting is limited to syslog, email (via system mailer), and script execution. There are no native integrations with modern incident management platforms. FastNetMon Advanced adds Slack and email notifications, plus webhook support for custom integrations. These are functional but basic compared to purpose-built alerting platforms.

Flowtriq supports seven notification channels natively: Discord, Slack, email, SMS, PagerDuty, OpsGenie, and custom webhooks. Each channel can be configured per severity level, per attack type, or per node. Alert messages include attack classification, severity, affected node, peak metrics, and a direct link to the incident page in the dashboard. PagerDuty and OpsGenie integrations support incident creation and resolution, enabling automatic escalation workflows.

For teams that use modern incident management, Flowtriq's native PagerDuty and OpsGenie integrations eliminate the need for middleware or custom scripts to bridge the gap between detection and response workflows. For FastNetMon, achieving the same level of integration requires external scripting and maintenance.

PCAP and Forensics

FastNetMon does not capture PCAP. Neither the Community nor Advanced edition has any built-in packet capture capability. If you need packet-level evidence of an attack — for forensic analysis, for upstream abuse reports, or for post-incident review — you need to run a separate tool (tcpdump, Wireshark, or a dedicated PCAP solution) alongside FastNetMon and coordinate the capture timing yourself.

Flowtriq captures PCAP automatically for every detected incident. The agent maintains a rolling buffer, and when an attack triggers, the buffer is written to disk with a configurable pre-attack window. This means you get packet data from before the attack started, which is critical for understanding how the attack ramped up and whether there were precursor patterns. PCAP files are downloadable directly from the incident page in the dashboard.

PCAP evidence is increasingly important for upstream mitigation requests. Many transit providers and hosting companies will not act on DDoS reports unless you can provide packet captures demonstrating the attack. Having this automatically captured and stored for every incident saves hours of manual effort and ensures you never miss the capture window.

Pricing Comparison

FastNetMon Community is free and open source. For organizations with existing network infrastructure that exports flow data, it provides basic threshold detection and BGP blackhole at zero software cost. The real cost is operational: Community requires manual configuration, has no web interface, limited alerting, and no attack classification. The engineering time to deploy, tune thresholds, maintain, and respond to alerts without rich incident data is the hidden cost.

FastNetMon Advanced pricing is quote-based and varies by deployment size. Based on publicly available information and community reports, typical pricing ranges from $500 to $2,000+ per month for small to mid-size deployments, with enterprise pricing scaling higher. FastNetMon does not publish fixed pricing on their website, so exact numbers require contacting their sales team. There is also an infrastructure prerequisite: you need routers or switches capable of exporting NetFlow, sFlow, or IPFIX, and a BGP session for blackhole signaling.

Flowtriq is $9.99 per node per month on monthly billing, or $7.99 per node per month on annual billing. A 10-node deployment costs $99.90/month ($79.90/month annual). A 50-node deployment costs $499.50/month ($399.50/month annual). There are no tiers, no per-feature upsells, and no minimum commitments on monthly billing. Every node gets all features: classification, PCAP, firewall rules, all seven alert channels, and full dashboard access. There is a 7-day free trial with no credit card required.

The infrastructure prerequisite difference is significant. FastNetMon requires flow-exporting network equipment and BGP infrastructure — which most hosting providers and ISPs already have, but many organizations running bare-metal servers, VPS fleets, or cloud instances do not. Flowtriq requires only a Linux server with a network interface.

Deployment and Operations

FastNetMon Community is deployed from source or packages on a Linux server that receives flow data. Configuration involves setting up flow collection (specifying which interfaces to listen on, which flow protocols to accept), defining detection thresholds (per-host PPS, BPS, and flow limits), and configuring BGP peering for blackhole announcement. For experienced network engineers, this is straightforward. For application teams or DevOps engineers without deep networking backgrounds, the learning curve is steep.

FastNetMon Advanced simplifies some of this with a web interface and guided configuration, but the underlying complexity remains. You still need flow-exporting network equipment, BGP infrastructure, and network engineering expertise to tune thresholds and manage blackhole behavior.

Flowtriq deployment is an agent install — a single command on each server. The agent auto-detects network interfaces, establishes a dynamic baseline over the first 24 hours, and begins detecting immediately with conservative default thresholds that tighten as the baseline matures. Configuration is done through the cloud dashboard, and changes propagate to agents automatically. No flow infrastructure, no BGP configuration, no threshold tuning required for basic operation.

Ongoing operational burden follows the same pattern. FastNetMon requires threshold tuning as traffic patterns change, BGP session monitoring, flow collection health checks, and manual investigation of each alert using external tools (since Community has no dashboard and Advanced has limited incident detail). Flowtriq's dynamic baselines adapt automatically, incidents are self-contained with all relevant data, and the dashboard provides the investigation interface.

When to Choose Each

Choose FastNetMon Community when:

• You are a hosting provider or ISP with existing flow-exporting infrastructure and BGP capability, and you need basic volumetric detection with automated blackhole as a free, open-source starting point.
• Your primary use case is protecting IP ranges at the network edge, not individual servers, and you have network engineers on staff who are comfortable tuning thresholds and managing BGP sessions.
• Budget is zero and you are willing to accept the operational tradeoffs: no classification, no PCAP, no modern alerting, no dashboard.

Choose FastNetMon Advanced when:

• You need flow-based detection with a web interface, basic alerting, and per-host visibility, and your network infrastructure already exports flow data.
• You are a service provider that needs to detect and blackhole attacks across a large IP space using aggregated flow data from backbone routers.
• You have Flowspec-capable upstream providers and want to use BGP Flowspec for more granular mitigation than simple blackhole.

Choose Flowtriq when:

• You need per-server detection with one-second granularity and cannot afford the blind spots that flow sampling introduces for short-duration or lower-volume attacks.
• You need automatic attack classification to know what type of attack is hitting each server, not just that traffic has spiked.
• You need PCAP evidence captured automatically for every incident, without running separate capture tools and hoping you catch the window.
• You want targeted firewall rules that keep servers online during attacks rather than binary blackhole that takes the target offline entirely.
• Your infrastructure is server-based (bare metal, VPS, cloud instances) without flow-exporting network equipment or BGP infrastructure.
• You want modern alerting (Discord, Slack, PagerDuty, OpsGenie) natively integrated without custom scripting.
• You want a cloud dashboard with full incident detail, historical analytics, and team collaboration features without self-hosting a web application.

Using Both Together

For service providers and hosting companies with existing flow infrastructure, running FastNetMon and Flowtriq together can make sense. FastNetMon monitors aggregate traffic at the network edge and triggers BGP-based mitigation for large volumetric attacks that need to be dropped before they saturate transit links. Flowtriq runs on critical servers to provide the per-host detection depth, attack classification, PCAP capture, and targeted mitigation that FastNetMon cannot deliver.

In this hybrid model, FastNetMon is your coarse-grained, network-wide safety net, and Flowtriq is your fine-grained, per-server detection and forensics layer. FastNetMon catches the 500 Gbps attacks that would saturate your uplinks. Flowtriq catches the 50,000 PPS attacks that FastNetMon's sampling misses, classifies them, captures evidence, and applies targeted mitigation that keeps the server running.

The Bottom Line

FastNetMon is a capable flow-based detection tool with a strong open-source foundation. For service providers with existing NetFlow/sFlow infrastructure and BGP capabilities, it is a proven option for network-wide volumetric detection and blackhole mitigation. Its weaknesses — sampling blind spots, no attack classification, no PCAP, limited alerting, binary mitigation — are inherent to the flow-based approach, not engineering deficiencies.

Flowtriq is purpose-built for per-server DDoS detection and goes deeper on every dimension that matters for incident response: one-second detection, eight-family classification with confidence scores, automatic PCAP capture, 22 firewall rule action types, and seven native alert channels. The tradeoff is that Flowtriq monitors individual servers rather than aggregate network traffic — it sees everything on each node but does not provide the backbone-wide visibility that FastNetMon offers to service providers.

For most organizations running servers that need DDoS protection, Flowtriq delivers more detection depth, richer incident data, and faster response at a lower total cost than FastNetMon Advanced. If you are a service provider with flow infrastructure already in place, FastNetMon Community or Advanced may be the right network-layer tool, and Flowtriq is the right server-layer complement.

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