Measuring minrelaytxfee across the Bitcoin network

The exploration of Bitcoin's network through a specialized scan has yielded intriguing insights into the minimum relay fees advertised by nodes, offering a unique lens into network behavior and node configuration. Utilizing a modified version of virtu’s p2p-crawler, the analysis targeted reachable nodes to record their FEEFILTER messages, focusing only on those accepting inbound connections. The absence of a FEEFILTER message within a three-minute window was noted, without delving into further validation such as test transactions or relay monitoring. The study spanned across two full scans conducted on the 10th and 15th of September.

The findings reveal a significant majority of nodes, approximately 89% in the initial scan and 86.5% in the subsequent one, advertising a minimum relay fee of 1000 satoshis. However, a noteworthy portion did not send a FEEFILTER message, hinting at potential operational peculiarities or the presence of spy nodes, as suggested by Peter Todd. This was particularly evident among IPv4 nodes, where an increased percentage was observed not sending FEEFILTER messages. The research also flagged a small fraction of nodes with unusually high minimum relay fees of 9170997 satoshis, a curiosity that remains unexplained but was independently verified for accuracy using Bitcoin Core.

The network-by-network breakdown offers additional detail, illustrating variances across different network types (i2p, IPv4, IPv6, onion_v3). For instance, i2p and onion_v3 networks showcased a higher compliance with the 1000 satoshi minimum fee, whereas IPv4 and IPv6 networks had more instances of no FEEFILTER message being sent. This nuanced distribution underscores the heterogeneity within the network and raises questions about node configurations and intentions.

This comprehensive analysis was inspired by discussions within the cryptocurrency community, notably tweets from Murch and insights from Peter Todd. Such collaborative efforts underscore the value of shared knowledge and curiosity in unraveling the complexities of blockchain networks. The discrepancies and anomalies identified through this scanning endeavor highlight areas for further investigation and discussion, contributing to a deeper understanding of network dynamics and node behavior in the decentralized ecosystem of Bitcoin.