Fortinet v. ForeScout Technologies: Five-Patent NAC Dispute Ends in Joint Dismissal
Fortinet filed suit against ForeScout Technologies in May 2020 asserting five US patents covering network access control and security infrastructure, targeting ForeScout’s CounterACT platform and related appliances. After nearly five years of litigation across two competing patent portfolios, the parties jointly stipulated to dismiss all claims — infringement counts with prejudice, invalidity counterclaims without — each side absorbing its own costs.
A Mutual Standoff: How Two Competing NAC Portfolios Cancelled Each Other Out
Fortinet, Inc. initiated this action on 15 May 2020 in the Northern District of California, asserting five patents — US8458314B1, US9369299B2, US9948662B2, US9503421B2, and US9894034B2 — against ForeScout Technologies’ CounterACT network access control platform, its 5100 Series appliances, SecureConnector, and related virtual and physical appliance lines. The asserted patents span network admission control, device profiling, and security event management, technologies at the commercial heart of both companies’ enterprise security offerings.
The case concluded on 6 February 2025 via a joint Rule 41(a) stipulation. Fortinet’s five patent infringement counts and ForeScout’s six patent infringement counterclaims were each dismissed with prejudice, permanently extinguishing those specific claims. Notably, ForeScout’s declaratory judgment invalidity counterclaims — challenging the validity of Fortinet’s patents — were dismissed without prejudice, as were Fortinet’s mirror invalidity counterclaims, leaving open the theoretical possibility of future validity challenges in a different proceeding.
The near five-year duration and the bilateral nature of the dismissal — with each party absorbing its own fees — strongly suggests a negotiated commercial resolution, most likely a cross-licensing arrangement or a business-level settlement, though the public record is silent on any financial terms. The without-prejudice dismissal of invalidity claims is a structurally significant detail: it means neither party secured a clean bill of health for its patents from the court, and those validity questions remain technically unresolved, which could matter in any future dispute between these competitors or with third parties.
Filing to Case Dismissed in 1728 days
1,728 days — nearly 5 years, well above the median N.D. Cal. patent case duration
Joint stipulated dismissal: what the split terms mean for both parties
Rule 41(a) joint stipulation: parties control the exit
A Rule 41(a) stipulated dismissal requires both parties’ agreement, signalling that neither side faced a court-imposed outcome. The split structure here — with prejudice on infringement, without prejudice on invalidity — is a deliberate negotiated result. ‘With prejudice’ on infringement means these specific claims cannot be re-filed. The invalidity carve-out without prejudice is atypical and suggests the parties declined to resolve underlying patent validity questions as part of their deal.
Mutual exit, no merits rulingWith-prejudice dismissal bars any re-filing on these claims
Both Fortinet’s five infringement counts and ForeScout’s six infringement counterclaims were dismissed with prejudice. This is a permanent bar: neither party can re-litigate the same infringement theories against the same products in a new action. In practice, this functions as a mutual release of the asserted infringement claims, even without a formal settlement agreement appearing in the public record. It is consistent with a cross-licence or a covenant-not-to-sue being executed privately.
Permanent bar on re-filingInvalidity dismissed without prejudice — validity questions unresolved
ForeScout’s declaratory judgment invalidity counterclaims (Counts II–VI) and Fortinet’s mirror invalidity counterclaims were dismissed without prejudice. This means the validity of all five Fortinet patents — and any ForeScout patents challenged — was never adjudicated. Both portfolios emerge from this litigation without a court ruling on their validity, which is a meaningful distinction from a full settlement that includes a consent judgment. Third parties and future challengers may still raise invalidity in IPR or subsequent litigation.
Validity unresolvedMutual cost absorption signals balanced negotiating leverage
The ‘each party bears its own costs’ provision is a standard hallmark of a commercially balanced exit. Neither side extracted a fee award, suggesting neither achieved a litigation position dominant enough to demand cost-shifting. For a dispute spanning nearly five years and involving ten-plus attorneys per side from firms including Ropes & Gray, Skadden, and Winston & Strawn, the mutual cost absorption implies the commercial value of the resolution — likely a cross-licence — outweighed the litigation economics for both parties.
Likely cross-licence resolutionFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Fortinet, Inc. | Company | Network security company — holder of US8458314B1 and four further NAC patentsSearch in Eureka ↗ |
| Defendant | ForeScout Technologies, Inc. | Company | Enterprise network access control vendor — maker of CounterACT and ForeScout appliance platformSearch in Eureka ↗ |
| Plaintiff counsel | Anthony P. Biondo | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Caroline W Van Ness | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Daniel Silverman | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Douglas R. Nemec | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | James Y. Pak | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | John M. Neukom | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Lana Robins | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Leslie Ann Demers | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Lindsay Cooper Hayman | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Rachel R. Blitzer | Attorney | Counsel for Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Debevoise & Plimpton LLP | Law Firm | Representing Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Latham & Watkins LLP | Law Firm | Representing Fortinet, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Skadden Arps Slate Meagher & Flom LLP | Law Firm | Representing Fortinet, Inc.Search in Eureka ↗ |
| Defendant counsel | Allen S. Cross | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Eimeric Reig-Plessis | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Hyun Min Han | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | James Lawrence Davis , Jr. | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | James R. Batchelder | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Jolene L. Wang | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Katherine Vidal | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Kelly C. Hunsaker | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Kimball Richard Anderson | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Matthew A. Hopkins | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Matthew R. McCullough | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Saishruti Mutneja | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant counsel | Shong Yin | Attorney | Counsel for ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant law firm | Irell & Manella LLP | Law Firm | Representing ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant law firm | Ropes & Gray LLP | Law Firm | Representing ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant law firm | Winston Strawn LLP | Law Firm | Representing ForeScout Technologies, Inc.Search in Eureka ↗ |
| Defendant law firm | Winston Strawn LLP (Chicago) | Law Firm | Representing ForeScout Technologies, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | California Northern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The joint stipulation’s split structure carries significant legal weight. Dismissing infringement claims with prejudice operates as a res judicata bar on those specific causes of action, meaning neither Fortinet nor ForeScout can re-litigate the same infringement theories against the same accused products. The without-prejudice carve-out for invalidity declaratory judgment claims is the more unusual provision: it confirms that the validity of each party’s asserted patents was never placed before the court for adjudication, leaving both portfolios legally intact but judicially untested. The ‘own costs’ provision forecloses any fee-shifting arguments under 35 U.S.C. § 285.
US8458314B1 and four further NAC patents — network access control and security event management
The five asserted patents — US8458314B1, US9369299B2, US9948662B2, US9503421B2, and US9894034B2 — span the core technical architecture of network access control (NAC) systems: device discovery, profiling, policy enforcement, and security event correlation. Application dates range from 2009 (US8458314B1, App. No. 12/916682) through 2015 (US9948662B2, App. No. 14/815458), placing their priority dates squarely in the era when NAC evolved from perimeter-based approaches to identity- and context-aware enforcement models.
Strategically, these patents sit at the intersection of NAC, SIEM, and network visibility — a convergence zone where Fortinet (FortiGate, FortiNAC, FortiSIEM) and ForeScout (CounterACT, EyeControl) compete directly. The portfolio’s breadth across both hardware appliances and virtual deployments means it creates risk for any vendor offering agentless device visibility or automated network segmentation. Because no validity ruling was issued in this case, these patents retain full presumptive enforceability, making them live enforcement assets against the broader enterprise security market.
Should you run an FTO against Fortinet’s NAC patent portfolio?
Any company developing or commercialising network access control platforms, agentless device profiling tools, network visibility appliances, or SIEM-integrated policy enforcement systems should treat Fortinet’s five-patent portfolio as an active clearance priority. The with-prejudice dismissal of ForeScout’s infringement claims removes one competitor from the risk picture, but Fortinet retains full rights to assert these patents against third parties. Products offering automated device classification, endpoint compliance enforcement, or network segmentation orchestration fall squarely within the technical scope suggested by the application summaries.
PatSnap Eureka’s FTO Search Agent can map each of the five asserted patents — US8458314B1, US9369299B2, US9948662B2, US9503421B2, and US9894034B2 — against your product architecture, identify overlapping claims, surface prior art that could support IPR petitions, and benchmark Fortinet’s portfolio against competing NAC and network security patent families. For R&D teams designing next-generation NAC or zero-trust network access (ZTNA) solutions, proactive clearance against this portfolio is a commercially sound risk management step.
Run a freedom-to-operate analysis on US8458314B1 to assess your product’s exposure
Run FTO in Eureka →Similar network access control and enterprise security patent cases
Explore comparable NAC and enterprise network security patent infringement actions filed in the Northern District of California and related federal venues.
What this case signals for the enterprise network security IP landscape
A five-year bilateral NAC patent war ending in mutual dismissal reveals how portfolio depth shapes leverage — and settlement structure.
Counter-assertion is a credible defence strategy in NAC and network security
ForeScout’s response to Fortinet’s five-patent suit was to assert six patents of its own, plus a tortious interference claim. This escalation — typical in mature enterprise security markets — suggests both companies had invested in portfolios capable of creating mutual exposure. Companies operating in NAC, SIEM, or network visibility should audit their freedom-to-operate position before litigation risk crystallises.
With-prejudice infringement / without-prejudice invalidity is a deliberate structural choice
The split dismissal structure preserves each party’s ability to challenge patent validity in future proceedings — for example, via IPR at the USPTO — while eliminating the specific litigation threat. This is a sophisticated exit that narrows commercial risk without fully resolving portfolio quality. IP counsel should note this template as a potential negotiating structure in complex bilateral disputes.
Fortinet v ForeScout — key questions answered
Fortinet filed patent infringement claims against ForeScout in May 2020 asserting five NAC and network security patents. After 1,728 days, the parties jointly stipulated to dismiss all claims: infringement counts on both sides dismissed with prejudice, invalidity declaratory judgment counterclaims dismissed without prejudice, and each party bearing its own costs.
Fortinet asserted US8458314B1, US9369299B2, US9948662B2, US9503421B2, and US9894034B2 — five patents covering network access control, device profiling, policy enforcement, and security event management. The accused products included ForeScout’s CounterACT platform, 5100 Series appliances, SecureConnector, and virtual appliance lines.
Infringement claims dismissed with prejudice cannot be re-filed — it is a permanent bar on those specific causes of action. The invalidity declaratory judgment counterclaims, dismissed without prejudice, were not adjudicated on the merits; either party could theoretically raise validity challenges in a future IPR proceeding or separate litigation, though the commercial context makes that unlikely in the near term.
No court-issued merits ruling was made. The case ended by joint stipulation with no finding of infringement, validity, or invalidity. The mutual cost-bearing provision and bilateral with-prejudice dismissal of infringement claims is consistent with a commercially negotiated resolution — likely a cross-licence — but no financial or licensing terms appear in the public record.
Yes. Because invalidity was dismissed without prejudice and no court ruled on the merits of any validity challenge, all five patents — US8458314B1, US9369299B2, US9948662B2, US9503421B2, and US9894034B2 — retain their statutory presumption of validity under 35 U.S.C. § 282 and remain assertable against third parties operating in the network access control, SIEM, or network visibility space.
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