fix(server): stop advertising Windows hotspot and VPN tunnel addresses as LAN routes

apps/server/src/environment/DirectEndpoints.test.ts

@@ -166,6 +166,24 @@ describe("resolveBoundEndpoints", () => {
     }
   });
 
+  it("omits Windows hotspot adapters and 198.18.0.0/15 VPN tunnels from a wildcard bind", () => {
+    const interfaces = {
+      ...INTERFACES,
+      "Local Area Connection* 2": virtualInterface("192.168.137.1"),
+      "LAN-Verbindung* 10": virtualInterface("192.168.137.2"),
+      utun40: virtualInterface("198.19.2.2"),
+    };
+    expect(
+      resolveBoundEndpoints({ platform: "win32", host: "0.0.0.0", port: 3773, interfaces }),
+    ).toEqual([
+      { kind: "lan", httpBaseUrl: "http://192.168.1.10:3773/" },
+      { kind: "tailnet", httpBaseUrl: "http://100.101.102.103:3773/" },
+    ]);
+    expect(
+      resolveBoundEndpoints({ platform: "darwin", host: "198.19.2.2", port: 3773, interfaces }),
+    ).toEqual([{ kind: "lan", httpBaseUrl: "http://198.19.2.2:3773/" }]);
+  });
+
   it("tags only addresses on Tailscale's interface as tailnet, not other VPNs in its range", () => {
     const interfaces = {
       en0: INTERFACES.en0,

apps/server/src/environment/DirectEndpoints.ts

@@ -23,7 +23,12 @@ import {
 } from "@t3tools/shared/hostClassification";
 
 import * as ServerConfig from "../config.ts";
-import { isLoopbackHost, isPrivateNetworkAddress, VIRTUAL_INTERFACE } from "../startupAccess.ts";
+import {
+  isLoopbackHost,
+  isPrivateNetworkAddress,
+  isVpnTunnelAddress,
+  VIRTUAL_INTERFACE,
+} from "../startupAccess.ts";
 
 type NetworkInterfacesMap = ReturnType<typeof NodeOS.networkInterfaces>;
 
@@ -75,6 +80,7 @@ export function resolveBoundEndpoints(input: {
             !entry.internal &&
             entry.family === "IPv4" &&
             isAdvertisableAddress(entry.address) &&
+            !isVpnTunnelAddress(entry.address) &&
             !(input.platform === "win32" && WINDOWS_HOST_ADAPTER_MAC.test(entry.mac)),
         )
         .map((entry) => entry.address)

apps/server/src/startupAccess.test.ts

@@ -57,6 +57,15 @@ it("prefers a LAN address over a tailnet one for a private-network pairing URL",
   ).toBe("http://192.168.1.42:3773");
 });
 
+it("skips a VPN tunnel address for a private-network pairing URL", () => {
+  expect(
+    resolveHeadlessConnectionString("0.0.0.0", 3773, {
+      interfaces: { utun40: [ipv4("198.19.2.2")], en0: [ipv4("192.168.1.42")] },
+      privateNetworkOnly: true,
+    }),
+  ).toBe("http://192.168.1.42:3773");
+});
+
 it("targets the bound interface when the listener binds a specific address", () => {
   const hostFor = (ip: string) =>
     loopbackUrlHostForAddress(NetAddress.inetAddressFromIpStringUnsafe(ip, 3773));

apps/server/src/startupAccess.ts

@@ -39,13 +39,12 @@ export const isLoopbackHost = (host: string | undefined): boolean => {
 };
 
 /**
- * Container and VM networks (Docker, libvirt, VMware, VirtualBox, Hyper-V, and
- * macOS's `bridge100`+) have private addresses only this machine reaches. A
- * host bridge such as `br0` or Proxmox's `vmbr0` carries the LAN address, so
- * it stays listed.
+ * Container and VM networks, macOS's `bridge100`+, and Windows' hidden virtual
+ * adapters such as the hotspot's localized `Local Area Connection* 2` reach only
+ * this machine's guests or tethered devices. A host bridge such as `br0` carries the LAN.
  */
 export const VIRTUAL_INTERFACE =
-  /^(docker|br-|veth|virbr|vmnet|vboxnet|vEthernet|podman|cni|flannel|cali|lxcbr|lxdbr|bridge[1-9]\d\d)/;
+  /^(docker|br-|veth|virbr|vmnet|vboxnet|vEthernet|podman|cni|flannel|cali|lxcbr|lxdbr|bridge[1-9]\d\d)|\* \d+$/;
 
 /**
  * Loopback or private-range IPv4 (LAN, tailnet, CGNAT), not link-local, in
@@ -56,6 +55,9 @@ export const isPrivateNetworkAddress = (address: string): boolean => {
   return NodeNet.isIPv4(ipv4) && !ipv4.startsWith("169.254.") && isPrivateNetworkHost(ipv4);
 };
 
+/** VPN and proxy clients put their tunnels in 198.18.0.0/15 (RFC 2544), which is never a LAN. */
+export const isVpnTunnelAddress = (address: string): boolean => /^198\.1[89]\./.test(address);
+
 /**
  * A private-network listener binds every interface but serves only
  * connections that stay on loopback, a LAN, or the tailnet. Both ends must be
@@ -102,7 +104,8 @@ const resolveHeadlessConnectionHost = (
     (entry) =>
       !entry.internal &&
       isIpv4Family(entry.family) &&
-      (!privateNetworkOnly || isPrivateNetworkAddress(entry.address)),
+      (!privateNetworkOnly ||
+        (isPrivateNetworkAddress(entry.address) && !isVpnTunnelAddress(entry.address))),
   );
   // A tailnet or other CGNAT address reaches fewer devices than the LAN one.
   const externalIpv4 = privateNetworkOnly