Firewall Traversal via Email-Initiated Outbound Connections
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Solution Overview
Problem
Firewalls in local area networks prevent remote access and configuration of devices, increasing maintenance costs and difficulties due to their restrictive inbound connection policies, especially when devices are leased and require external management.
Innovation Solution
A method allowing remote devices to initiate network connections with devices behind a firewall by using electronic mail messages to instruct state machines to establish connections, enabling monitoring and configuration through SNMP or other protocols over TCP/IP connections, potentially secured with SSL or S-HTTP, bypassing firewall restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firewall is implemented to protect the local network, then network security is improved, but remote access to devices for monitoring and configuration is blocked
Solution Approach 1:
The state machine is pre-configured with the capability to initiate outbound connections and the necessary communication protocols. When a remote device needs to access it, the state machine proactively establishes an outbound connection to the remote device, bypassing the firewall's inbound blocking rule while maintaining security. This preliminary preparation of communication capability resolves the contradiction between security and remote accessibility.
Solution Approach 2:
Instead of allowing inbound connections from remote devices to the state machine (which would compromise security), the solution inverts the connection direction: the state machine initiates outbound connections to remote devices. This reversal maintains firewall security while enabling the required remote monitoring and configuration functionality.
2Ease of operation
If manual browsing to each device is used for configuration, then device control is achieved, but time and effort increase significantly
Solution Approach 1:
The state machine provides self-service capabilities by automatically responding to remote access requests and managing its own configuration state. Remote devices can send requests to the state machine, which then autonomously establishes connections and executes configuration commands without requiring manual intervention for each device, significantly reducing configuration time while maintaining full device control.
Solution Approach 2:
The state machine implements a universal interface that accepts various types of requests (monitoring, configuration, maintenance) from different remote devices through a common protocol. This multi-functional capability allows a single remote access mechanism to handle multiple operations across multiple devices, eliminating the need for separate manual browsing processes for each device and operation type.
Data Source
AI summary
Traversing a firewall. A method embodiment includes receiving, from behind the firewall, an electronic mail message with instructions to establish a connection with a device located outside the firewall. A connection is then established through the firewall with the device outside the firewall according to the instructions in the electronic mail message.