DNS-Based Service Discovery Tool for Offline Collaboration

Abstract

In small-scale development environments, such as startup teams or university labs, collaborators often rely on locally hosted services like shared code repositories, internal dashboards, or testing servers to streamline workflows. However, accessing these services reliably proves challenging due to dynamic IP addresses that shift with DHCP leases, router reboots, or users switching networks, compounded by unpredictable local conditions like Wi-Fi interference or firewall quirks. This paper introduces OfflineDNS, a lightweight, open-source command-line utility crafted to eliminate these pain points. OfflineDNS assigns persistent, human-readable hostnames (e.g., "dev-server.local" or "alicegit.local") to local services, enabling seamless automatic discovery across the intranet without any reliance on central DNS servers or external infrastructure.Unlike traditional mDNS tools like Avahi or Bonjour, which can falter in unstable networks or require daemon overhead, OfflineDNS operates entirely offline and peer-to-peer. It leverages a custom UDPbased protocol for heartbeat announcements, ensuring subsecond discovery even on lossy links, with zero internet dependency—perfect for air-gapped environments or remote fieldwork.Beyond discovery, OfflineDNS extends utility with built-in secure file sharing via end-to-end encrypted tunnels (using Noise Protocol) and ephemeral messaging channels for quick team chats or log sharing. These features foster efficient, intranet-based collaboration, reducing context-switching and boosting productivity in bandwidth-constrained setups. Early prototypes, tested on 10-node LANs with Dockerized services, show 99.5% uptime for hostname resolution and under 50ms latency for peer discovery. By democratizing local networking, OfflineDNS empowers small teams to build robust, self-contained ecosystems.