Inter-Node NAT Detection via Encapsulated IP Header Comparison
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Solution Overview
Problem
Existing secure communication protocols like IPsec face challenges in determining the presence of Network Address Translation (NAT) devices in deployment environments, which affects secure communication guarantees, and current NAT detection methods are complex and risk internal IP address exposure.
Innovation Solution
A method for inter-network-node NAT detection involving IP message encapsulation and protection processing of request and response messages, allowing nodes to determine the presence and position of NATs independently of key management protocols, ensuring secure and efficient detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current NAT detection methods are used, then NAT detection can be performed, but the detection process is complex and risks internal IP address exposure
Solution Approach 1:
The patent introduces an intermediary encapsulation mechanism where the original IP packet is wrapped within a new IP packet. This intermediary structure allows NAT detection without directly exposing internal IP addresses, as the detection is performed on the outer packet headers while the inner original packet remains protected. The intermediary encapsulation layer acts as a buffer that enables detection functionality while maintaining security.
Solution Approach 2:
The detection process is segmented into distinct phases: encapsulation phase where the original packet is wrapped, transmission phase where the encapsulated packet traverses the network, and detection phase where NAT elements are identified by comparing outer packet headers. This segmentation allows the complex detection process to be broken down into manageable, secure steps that prevent internal address exposure while maintaining detection accuracy.
2Reliability
If IPsec secure communication protocol is deployed, then secure communication is guaranteed, but it is impossible to know whether there is a NAT device in the deployment environment
Solution Approach 1:
The patent performs preliminary NAT detection by analyzing the outer IP packet headers before the IPsec secure communication channel is fully established. This preliminary action allows the system to determine the presence of NAT devices in advance, enabling appropriate security configuration decisions to be made before sensitive communication begins, thus preventing loss of NAT device information while maintaining secure communication guarantees.
3Measurement precision
If internal IP addresses are used for detection, then detection accuracy is improved, but internal address leaks occur
Solution Approach 1:
The patent uses the outer IP packet headers as an intermediary for detection, rather than directly using internal IP addresses. The encapsulation mechanism allows detection to be performed on the outer layer addresses that are safe to expose, while the inner original packet containing sensitive internal addresses remains protected. This intermediary approach maintains detection precision by allowing header analysis while preventing harmful address leakage through proper encapsulation.
Solution Approach 2:
The detection process works on a copy of the packet structure (the outer encapsulated headers) rather than the original internal packet data. By creating and analyzing this copy structure, the system achieves detection accuracy without exposing the actual internal IP addresses contained in the original packet, thus preventing address leakage while maintaining measurement precision.
Data Source
AI summary
The present application discloses an NAT detection method between network nodes, a device, and a storage medium. The method includes: a request node obtains first node information, takes the obtained first node information as payload data of an NAT detection request message or an NAT detection result request message, performs IP packet encapsulation on the NAT detection request message or the NAT detection result request message, performs protection processing on an NAT detection request packet obtained after encapsulation, sends the NAT detection request packet to a response node; and the response node performs deprotection processing on the received NAT detection request packet and obtains the payload data of the NAT detection request message or the NAT detection result request message, compares the obtained payload data with corresponding content in a first IP header of the NAT detection request packet, and determines an NAT detection result according to the comparison result.