The expanding attack surface and increasing complexity of information systems render human responses insufficient against modern threats. The introduction of concepts such as self-protection and collaborative cybersecurity opens up possibilities for new defence systems tailored to today's requirements. Distributed Denial-of-Service (DDoS) attacks, in particular, demand automated and wide-reaching responses due to their disruptive nature and broad impact across networks. Recent research is exploring blockchain-based solutions to address the fundamental challenge of trust among collaborators, as blockchain provides a secure and transparent framework for sharing threat intelligence and enforcing consensus. However, the literature did not establish the relevance of blockchain technology for collaborative DDoS mitigation before its application. The contribution of this paper is twofold. First, we methodologically analyse the relevance of blockchain technology for our use-case and determine that Hyperledger Fabric (HLF) is a promising solution. Second, we evaluate the performance impacts of HLF combined with the SmartBFT consensus algorithm for collaborative DDoS attack mitigation. Our performance analysis measured system durations ranging from 200 to 1500 ms under various network configurations, influenced by topological size (number of nodes) and geographical size (communication delays). The modeling of our results showed quadratic scaling with the number of HLF orderers and stronger, linear scaling with communication delays. These findings provide actionable insights to optimise collaborative blockchain-based DDoS mitigation solutions.