Invalidity dossier
US 5623601
Apparatus and method for providing a secure gateway for communication and data exchanges between networks
Current assignee: Milkway Networks Corp
Added 9/21/2026, 10:40:01 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US5623601A
Title: Apparatus and method for providing a secure gateway for communication and data exchanges between networks.
Inventor: Hung T. Vu. Original assignee: Milkyway Networks Corp (recorded as MILKYWAY NETWORKS CORPORATION).
Key dates: Priority 1994-11-18 (claimed from CA002136150A); application US08/342,772 filed 1994-11-21; granted and published 1997-04-22. Legal status shown as "Expired - Lifetime," with anticipated expiration 2014-11-21.
Purpose: The application "relates generally to internetwork communications and data exchanges and, in particular, to secure gateways which serve as firewalls between computer networks to inhibit electronic vandalism and espionage." The stated problem is that private networks holding trade secrets and confidential information are vulnerable to unauthorized exposure, contamination, destruction, or retrieval when connected to public networks, unless interconnected through a secure gateway preventing unauthorized access from the public network.
Plain-language scope (per the excerpt): The text frames the invention against three firewall models—screening router, bastion host, and dual homed gateway—and against application-level ("proxy") gateways. It describes prior-art weaknesses: screening routers depend on administrative passwords and are vulnerable to "piggybacked" protocols; packet filters run in the operating system kernel with limited screening capacity and impractical rule bases (a UNIX TCP/IP system has 64K ports); dual homed gateways block TCP/IP forwarding but weaken security if users log in to the gateway; and application gateways, while secure, are "not transparent to the user," requiring extra operations or specially adapted network service programs (e.g., Telnet). The invention is positioned as a secure gateway addressing these shortcomings.
Source: https://patents.google.com/patent/[US5623601](/patent/US5623601)/en
What the excerpt does not establish: No claims, independent or dependent, are quoted, so the actual metes and bounds of the patent's coverage cannot be stated. The excerpt ends mid-sentence ("the user will optiona..."), so the description of the invention's own embodiment and any transparency mechanism is incomplete. Specific apparatus components, packet-handling steps, and figures are not provided. Nothing here establishes validity, enforceability, or the content of cited prior art. Litigation references and post-1998 assignment entries appear in the source page but are outside the requested scope.
Generated 10/1/2026, 10:01:23 PM
Cases on file (0)
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.