[bug] Coder Connect on Windows: DNS publishing silently fails — workspace lookups return empty answers despite Connect being on

使用 Resolve-DnsName 针对 fd60:627a:a42b::53 重现故障，然后检查 Coder Connect Windows service、Wintun adapter、NRPT rule 以及 CoderVpnService 的行为。当对 workspace.coder 的查询返回 IP 地址，并且重启 Coder Desktop service 后 adapter、rule 和 service registration 仍然保留时，即表示完成。

Version: 0.8.3 (latest)
OS: Windows 11 Pro 10.0.26200

Symptom

Coder Desktop GUI reports Connect is ON, workspaces are listed, but no workspace hostname (<workspace>.coder) actually resolves via DNS. Apps that rely on Coder Connect for hostname routing (in our case, Claude Desktop's bundled SSH client which cannot use ~/.ssh/config ProxyCommand) time out at the SSH handshake step because no IP is returned.

What's set up correctly

• Wintun adapter "Coder" is Up with a fd60:627a:a42b::/64 IPv6 prefix
• Get-DnsClientNrptRule shows .coder → fd60:627a:a42b::53
• TCP/53 on the Coder DNS server is reachable
• coder users show me succeeds — CLI is authenticated to our deployment

What fails

Direct query to the embedded DNS:

> Resolve-DnsName -Name myworkspace.coder -Server fd60:627a:a42b::53
(empty answer — no IPAddress, no NXDOMAIN)

> ssh -F nul -o ConnectTimeout=15 [email protected] "echo OK"
ssh: Could not resolve hostname myworkspace.coder: No such host is known.

Queries succeed only when going via the ~/.ssh/config ProxyCommand (coder.exe ssh --stdio) — i.e., bypassing Coder Connect entirely. OpenSSH with verbose shows Authenticated to myworkspace.coder (via proxy).

Additional observation

Restarting the "Coder Desktop" Windows service while signed in deletes the Wintun adapter, the NRPT rule, and the CoderVpnService entry. Recovery requires toggling Connect OFF/ON in the tray app — the service restart alone leaves the system in a broken state.

Impact

Any third-party app that integrates with Coder via direct DNS + TCP (no ProxyCommand support) — e.g., Claude Desktop's "Add SSH connection" feature — cannot reach workspaces, even when the GUI says Connect is healthy.