Tailcat utility faces macOS connectivity issues

Tailcat is an open-source, netcat-style utility designed to pipe data directly over the Tailscale data plane using WireGuard-encrypted tunnels. Unlike the standard Tailscale client, Tailcat operates without the Tailscale control plane, allowing users to exchange connection metadata out of band via short tokens. It functions as a userspace library and CLI tool that does not require root or admin access, as it does not alter machine routing tables or DNS settings.

Users on macOS have reported connectivity issues with Tailcat, including instances where peer connections fail to complete, hang indefinitely, or return handshake errors. These problems have been observed across macOS Sonoma, Sequoia, and Tahoe builds on both Apple Silicon and Intel hardware. Common causes for these failures include dismissed permission prompts, the Tailscale daemon being in a degraded state, MagicDNS resolution conflicts, ACL restrictions, or interference from macOS application firewalls and third-party security software.