US 5958015

Patent Overview: US 5,958,015

Title: Network session wall passively listening to communication session, with use of access rules, stops further communication between network devices by emulating messages to the devices

Patent number / application: US 5,958,015 A; application US08/739,518

Inventor: Ziv Dascalu

Assignee of record (as listed): Original — Abirnet Ltd; current — Abirnet Ltd / CA Software Israel Ltd

Key dates: Filed 1996-10-29; priority 1996-10-29; granted and published 1999-09-28; anticipated expiration 2016-10-29; status "Expired – Lifetime"

Source: https://patents.google.com/patent/US5958015/en

Purpose. The patent concerns local and wide area networks in which computers and other devices communicate using protocols, where a "session" is a conversation between a client that initiates it and a server that accepts. The invention monitors and controls such communications, restricting specific clients' access to specific servers for specific protocols or data content. It is positioned as an alternative to firewalls, which must sit inline, are limited by network-segment topology, and degrade throughput as a "network bottleneck."

Plain-language scope. A "session wall" device — network adapter, memory, processor, and a communication session control system — is attached to the network and passively listens: it receives communications not addressed to it without interfering with their transmission to the intended destination. It reads a portion of each communication and compares that data against stored access rules (network information plus a table of server groups, client groups, and rules between them, which may define logical and mathematical combinations). If a communication is not allowed, the session wall sends a message to at least one party — to a client, an emulated server message, session-ended or blocked notice; to a server, an emulated client message or a data string discouraging further responses. If an appropriate message fails, it issues a succession of protocol-conforming messages, limited by a timer, to avoid blocking the network indefinitely. Multiple cooperating session-wall devices may act as backups on one segment.

What the excerpt does not establish: the full claim set, complete description, drawing contents, detailed-embodiment specifics, and any legal conclusions about validity or enforceability.