chore: sync konduit-platform

konduit-platform/src/dns/linux.rs

@@ -31,6 +31,31 @@ trait Resolve1Manager {
     fn revert_link(&self, ifindex: i32) -> zbus::Result<()>;
 }
 
+// Per-link object (/org/freedesktop/resolve1/link/_<ifindex>), used only to
+// read back the physical interface's current DNS servers before we override
+// them, so they can be restored byte-for-byte on disconnect.
+//
+// SetLinkDefaultRoute (the "correct" API for demoting a link as a default DNS
+// route) requires interactive polkit auth (auth_admin_keep) — unlike
+// SetLinkDNS/SetLinkDomains, it does NOT get a CAP_NET_ADMIN bypass in
+// systemd-resolved, so it silently fails for this capability-only (non-root)
+// process. Reusing SetLinkDNS on the physical link's own object instead stays
+// on the bypass path.
+#[zbus::proxy(interface = "org.freedesktop.resolve1.Link", default_service = "org.freedesktop.resolve1")]
+trait Resolve1Link {
+    #[zbus(property, name = "DNS")]
+    fn dns(&self) -> zbus::Result<Vec<(i32, Vec<u8>)>>;
+}
+
+fn link_object_path(if_index: u32) -> String {
+    let mut path = String::from("/org/freedesktop/resolve1/link/");
+    for c in if_index.to_string().chars() {
+        path.push_str("_3");
+        path.push(c);
+    }
+    path
+}
+
 // ---------------------------------------------------------------------------
 // Public API
 // ---------------------------------------------------------------------------
@@ -38,6 +63,7 @@ trait Resolve1Manager {
 pub async fn set_dns(
     interface: &str,
     if_index: Option<u32>,
+    physical_if_index: Option<u32>,
     dns_servers: &[IpAddr],
     _assigned_ip: IpAddr,
     state: &mut DnsState,
@@ -59,6 +85,31 @@ pub async fn set_dns(
     match result {
         Ok(_) => {
             state.configured = true;
+            // Both the physical link and the tunnel link end up with
+            // Default Route: yes in systemd-resolved (the physical link
+            // never loses that flag just because another link gains it).
+            // With two "default route" resolvers, systemd-resolved can
+            // race queries between the VPN's DNS server and the ISP's,
+            // leaking lookups outside the tunnel and returning
+            // inconsistent/partial answers (e.g. AAAA-only responses).
+            // Blank out the physical link's own DNS server list so it has
+            // nothing to answer with, leaving the tunnel as the sole
+            // practical resolver; its original servers are saved and
+            // restored on disconnect.
+            if let Some(phys_idx) = physical_if_index {
+                match clear_physical_link_dns(phys_idx).await {
+                    Ok(original) => {
+                        state.demoted_physical_if_index = Some(phys_idx);
+                        state.physical_dns_backup = original;
+                    }
+                    Err(e) => {
+                        warn!(
+                            "Failed to clear physical interface {} DNS servers: {}",
+                            phys_idx, e
+                        );
+                    }
+                }
+            }
         }
         Err(e) => {
             warn!(
@@ -112,6 +163,18 @@ pub async fn restore(
     // Always run resolvectl revert as a second pass.
     revert_resolvectl(interface).await.ok();
 
+    // Restore the physical interface's original DNS servers we blanked out
+    // in set_dns, or it's left with no resolver after the VPN disconnects.
+    if let Some(phys_idx) = state.demoted_physical_if_index.take() {
+        let backup = std::mem::take(&mut state.physical_dns_backup);
+        if let Err(e) = restore_physical_link_dns(phys_idx, backup).await {
+            warn!(
+                "Failed to restore physical interface {} DNS servers: {}",
+                phys_idx, e
+            );
+        }
+    }
+
     state.configured = false;
     Ok(())
 }
@@ -165,6 +228,62 @@ async fn set_dns_dbus(if_index: u32, dns_servers: &[IpAddr]) -> Result<()> {
     Ok(())
 }
 
+/// Reads the physical link's current DNS servers, then blanks them out so it
+/// stops acting as a competing resolver. Returns the original list to restore
+/// later. Both the read and the clear go through the same CAP_NET_ADMIN
+/// bypass path as the tunnel's own SetLinkDNS call.
+async fn clear_physical_link_dns(if_index: u32) -> Result<Vec<(i32, Vec<u8>)>> {
+    let conn = zbus::Connection::system()
+        .await
+        .context("Failed to connect to D-Bus system bus")?;
+
+    let link_proxy = Resolve1LinkProxy::builder(&conn)
+        .path(link_object_path(if_index))
+        .context("Invalid link object path")?
+        .build()
+        .await
+        .context("Failed to create resolve1 link proxy")?;
+
+    let original = link_proxy
+        .dns()
+        .await
+        .context("Failed to read physical link DNS servers")?;
+
+    let manager_proxy = Resolve1ManagerProxy::new(&conn)
+        .await
+        .context("Failed to create resolve1 proxy")?;
+
+    manager_proxy
+        .set_link_dns(if_index as i32, vec![])
+        .await
+        .context("SetLinkDNS (clear) failed")?;
+
+    info!(
+        "Cleared physical interface {} DNS servers ({} saved for restore)",
+        if_index,
+        original.len()
+    );
+    Ok(original)
+}
+
+async fn restore_physical_link_dns(if_index: u32, original: Vec<(i32, Vec<u8>)>) -> Result<()> {
+    let conn = zbus::Connection::system()
+        .await
+        .context("Failed to connect to D-Bus system bus")?;
+
+    let proxy = Resolve1ManagerProxy::new(&conn)
+        .await
+        .context("Failed to create resolve1 proxy")?;
+
+    proxy
+        .set_link_dns(if_index as i32, original)
+        .await
+        .context("SetLinkDNS (restore) failed")?;
+
+    info!("Restored physical interface {} DNS servers", if_index);
+    Ok(())
+}
+
 async fn revert_link_dbus(if_index: u32) -> Result<()> {
     let conn = zbus::Connection::system()
         .await

konduit-platform/src/dns/mod.rs

@@ -16,6 +16,9 @@ pub struct DnsManager {
     interface: String,
     /// Interface index (if available/relevant)
     if_index: Option<u32>,
+    /// Pre-VPN default-gateway interface index, demoted as DNS default route
+    /// while connected (Linux only)
+    physical_if_index: Option<u32>,
     /// IP address assigned to the TUN interface
     assigned_ip: IpAddr,
     /// State to track if we modified DNS
@@ -26,14 +29,29 @@ pub struct DnsManager {
 struct DnsState {
     configured: bool,
     _original_dns: Vec<IpAddr>,
+    // Physical interface demoted from systemd-resolved's default DNS route
+    // (Linux only) while the tunnel is the default; restored on disconnect.
+    demoted_physical_if_index: Option<u32>,
+    // Physical interface's original DNS servers (address_family, raw_bytes),
+    // saved before blanking them out; restored verbatim on disconnect.
+    physical_dns_backup: Vec<(i32, Vec<u8>)>,
 }
 
 impl DnsManager {
-    /// Create a new DNS manager for a specific interface
+    /// Create a new DNS manager for a specific interface.
-    pub fn new(interface: String, if_index: Option<u32>, assigned_ip: IpAddr) -> Self {
+    /// `physical_if_index` is the pre-VPN default-gateway interface (Linux
+    /// only) — needed so the tunnel can become the sole default DNS
+    /// resolver instead of racing systemd-resolved queries against it.
+    pub fn new(
+        interface: String,
+        if_index: Option<u32>,
+        physical_if_index: Option<u32>,
+        assigned_ip: IpAddr,
+    ) -> Self {
         Self {
             interface,
             if_index,
+            physical_if_index,
             assigned_ip,
             state: Arc::new(Mutex::new(DnsState::default())),
         }
@@ -51,7 +69,7 @@ impl DnsManager {
         // Platform specific implementation
         #[cfg(target_os = "linux")]
         {
-            linux::set_dns(&self.interface, self.if_index, dns_servers, self.assigned_ip, &mut state).await?;
+            linux::set_dns(&self.interface, self.if_index, self.physical_if_index, dns_servers, self.assigned_ip, &mut state).await?;
         }
 
         #[cfg(target_os = "windows")]

konduit-platform/src/routes/linux.rs

@@ -1,8 +1,8 @@
 use anyhow::{Context, Result};
 use futures::stream::TryStreamExt;
-use netlink_packet_route::route::RouteProtocol;
+use netlink_packet_route::route::{RouteProtocol, RouteType};
 use rtnetlink::{new_connection, Handle, IpVersion};
-use std::net::{IpAddr, Ipv4Addr};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 use tracing::{info, warn};
 
 // Added with priority lower than typical policy-routing stacks (e.g., xray uses 9001).
@@ -25,10 +25,21 @@ pub struct RouteManager {
     // Saved during setup for re-adding the server host route after resume.
     server_ip: Option<Ipv4Addr>,
     wifi_gateway: Option<Ipv4Addr>,
+    // Physical interface the server host route must be pinned to. Without this,
+    // if the VPN's assigned tun subnet happens to contain the physical gateway
+    // IP (e.g. both are 10.x.0.1), the kernel resolves the gateway via tun0's
+    // own directly-connected route instead of the physical NIC, looping the
+    // server route back into the tunnel it's meant to bypass.
+    wifi_iface_index: Option<u32>,
     // Saved for re-adding the VPN default route after reconnect.
     vpn_gateway: Option<Ipv4Addr>,
     // True when we installed an ip rule to override policy-routing stacks.
     added_policy_rule: bool,
+    // True when we installed an IPv6 "unreachable" default route to block
+    // IPv6 leaks (full-tunnel mode only pushes an IPv4 default route via
+    // tun0, so without this, any AAAA-resolved destination would route out
+    // the physical NIC directly, bypassing the tunnel entirely).
+    added_ipv6_blackhole: bool,
 }
 
 impl RouteManager {
@@ -43,11 +54,13 @@ impl RouteManager {
             added_routes: Vec::new(),
             tun_interface: tun_interface.clone(),
             tun_index: None,
-            dns_manager: crate::dns::DnsManager::new(tun_interface, None, IpAddr::V4(Ipv4Addr::UNSPECIFIED)),
+            dns_manager: crate::dns::DnsManager::new(tun_interface, None, None, IpAddr::V4(Ipv4Addr::UNSPECIFIED)),
             server_ip: None,
             wifi_gateway: None,
+            wifi_iface_index: None,
             vpn_gateway: None,
             added_policy_rule: false,
+            added_ipv6_blackhole: false,
         })
     }
 
@@ -66,14 +79,18 @@ impl RouteManager {
         }
     }
 
-    async fn get_default_gateway(&self) -> Result<Ipv4Addr> {
+    /// Returns the physical default gateway and the interface it's reachable on.
+    /// The interface index must be used to pin any route meant to bypass the
+    /// tunnel — relying on gateway-only resolution lets the kernel route it via
+    /// tun0 instead if the VPN's assigned subnet happens to contain this gateway IP.
+    async fn get_default_gateway(&self) -> Result<(Ipv4Addr, u32)> {
         use netlink_packet_route::route::RouteAddress;
 
         let mut routes = self.handle.route().get(IpVersion::V4).execute();
         // Collect all default-route gateways with their metrics.
         // VPN default routes have low metric (50); physical/DHCP routes have high metric (600+).
         // We want the physical gateway, so take the one with the highest metric.
-        let mut candidates: Vec<(u32, Ipv4Addr)> = Vec::new();
+        let mut candidates: Vec<(u32, Ipv4Addr, u32)> = Vec::new();
 
         while let Some(route) = routes.try_next().await? {
             if route.header.destination_prefix_length != 0 {
@@ -81,25 +98,27 @@ impl RouteManager {
             }
             let mut metric = 0u32;
             let mut gateway: Option<Ipv4Addr> = None;
+            let mut oif: Option<u32> = None;
             for nla in route.attributes.iter() {
                 match nla {
                     netlink_packet_route::route::RouteAttribute::Gateway(
                         RouteAddress::Inet(ip),
                     ) => gateway = Some(*ip),
                     netlink_packet_route::route::RouteAttribute::Priority(m) => metric = *m,
+                    netlink_packet_route::route::RouteAttribute::Oif(idx) => oif = Some(*idx),
                     _ => {}
                 }
             }
-            if let Some(gw) = gateway {
+            if let (Some(gw), Some(idx)) = (gateway, oif) {
-                candidates.push((metric, gw));
+                candidates.push((metric, gw, idx));
             }
         }
 
         // Highest metric = physical/DHCP interface (not VPN).
         candidates
             .into_iter()
-            .max_by_key(|(m, _)| *m)
+            .max_by_key(|(m, _, _)| *m)
-            .map(|(_, gw)| gw)
+            .map(|(_, gw, idx)| (gw, idx))
             .ok_or_else(|| anyhow::anyhow!("No default gateway found"))
     }
 
@@ -126,11 +145,15 @@ impl RouteManager {
             self.tun_index.unwrap()
         );
 
-        let current_gateway = self
+        let (current_gateway, wifi_iface_index) = self
             .get_default_gateway()
             .await
             .context("Failed to get current gateway")?;
-        info!("Current gateway: {}", current_gateway);
+        self.wifi_iface_index = Some(wifi_iface_index);
+        info!(
+            "Current gateway: {} (interface index {})",
+            current_gateway, wifi_iface_index
+        );
 
         // Resolve server address to IP
         let server_ip = if let Ok(ip) = server_addr.parse::<IpAddr>() {
@@ -160,6 +183,7 @@ impl RouteManager {
                 .v4()
                 .destination_prefix(server_v4, 32)
                 .gateway(current_gateway)
+                .output_interface(wifi_iface_index)
                 .priority(VPN_ROUTE_METRIC)
                 .execute()
                 .await;
@@ -207,6 +231,7 @@ impl RouteManager {
             self.added_routes.push((Ipv4Addr::new(0, 0, 0, 0), 0));
 
             self.install_policy_rule().await;
+            self.block_ipv6_leak().await;
         } else {
             info!(
                 "Split-tunnel mode: adding {} routes via VPN...",
@@ -314,14 +339,59 @@ impl RouteManager {
         }
     }
 
+    /// Block outbound IPv6 in full-tunnel mode by installing an "unreachable"
+    /// default route (::/0). Full-tunnel only pushes an IPv4 default route
+    /// via the VPN gateway (VPN servers here don't provide IPv6 transport),
+    /// so without this, any destination that resolves to an AAAA record
+    /// leaks straight out the physical interface instead of the tunnel —
+    /// bypassing it entirely rather than merely failing closed. Failing the
+    /// IPv6 attempt fast also lets Happy-Eyeballs clients fall back to IPv4
+    /// (through the tunnel) quickly instead of hanging on an IPv6 path that
+    /// silently goes nowhere.
+    async fn block_ipv6_leak(&mut self) {
+        let result = self
+            .handle
+            .route()
+            .add()
+            .v6()
+            .destination_prefix(Ipv6Addr::UNSPECIFIED, 0)
+            .kind(RouteType::Unreachable)
+            .priority(VPN_ROUTE_METRIC)
+            .execute()
+            .await;
+
+        match result {
+            Ok(_) => {
+                self.added_ipv6_blackhole = true;
+                info!("✅ IPv6 default route blocked (prevents leaking outside tunnel)");
+            }
+            Err(e) => {
+                let err_msg = format!("{:?}", e);
+                if err_msg.contains("File exists")
+                    || err_msg.contains("EEXIST")
+                    || err_msg.contains("code: Some(-17)")
+                {
+                    self.added_ipv6_blackhole = true;
+                    warn!("IPv6 blackhole route already exists, continuing...");
+                } else {
+                    warn!("Failed to block IPv6 default route: {:?}", e);
+                }
+            }
+        }
+    }
+
     /// Setup DNS configuration
     pub async fn setup_dns(&mut self, dns_servers: &[IpAddr], assigned_ip: IpAddr) -> Result<()> {
         if dns_servers.is_empty() {
             return Ok(());
         }
 
-        self.dns_manager =
+        self.dns_manager = crate::dns::DnsManager::new(
-            crate::dns::DnsManager::new(self.tun_interface.clone(), self.tun_index, assigned_ip);
+            self.tun_interface.clone(),
+            self.tun_index,
+            self.wifi_iface_index,
+            assigned_ip,
+        );
 
         self.dns_manager.set_dns(dns_servers).await
     }
@@ -344,16 +414,18 @@ impl RouteManager {
             _ => return Ok(()),
         };
 
-        let result = self
+        let mut req = self
             .handle
             .route()
             .add()
             .v4()
             .destination_prefix(server_ip, 32)
             .gateway(gateway)
-            .priority(VPN_ROUTE_METRIC)
+            .priority(VPN_ROUTE_METRIC);
-            .execute()
+        if let Some(idx) = self.wifi_iface_index {
-            .await;
+            req = req.output_interface(idx);
+        }
+        let result = req.execute().await;
 
         match result {
             Ok(_) => {
@@ -484,6 +556,28 @@ impl RouteManager {
             self.added_policy_rule = false;
         }
 
+        if self.added_ipv6_blackhole {
+            let mut routes = self.handle.route().get(IpVersion::V6).execute();
+            let mut to_delete = None;
+            while let Some(route) = routes.try_next().await? {
+                if route.header.destination_prefix_length == 0
+                    && route.header.kind == RouteType::Unreachable
+                {
+                    to_delete = Some(route);
+                    break;
+                }
+            }
+
+            match to_delete {
+                Some(route) => match self.handle.route().del(route).execute().await {
+                    Ok(()) => info!("Removed IPv6 blackhole route"),
+                    Err(e) => warn!("Failed to delete IPv6 blackhole route: {:?}", e),
+                },
+                None => warn!("IPv6 blackhole route not found, nothing to remove"),
+            }
+            self.added_ipv6_blackhole = false;
+        }
+
         if self.added_routes.is_empty() {
             return Ok(());
         }

konduit-platform/src/routes/macos.rs

@@ -7,6 +7,12 @@ pub struct MacOsNetManager {
     server_host: String,
     original_gateway: String,
     primary_service: String,
+    // Physical interface the server host route must be pinned to via -ifscope.
+    // Without this, if the VPN's assigned tun subnet happens to contain the
+    // physical gateway IP, the OS can resolve the gateway via the tun
+    // interface's own directly-connected route instead of the physical NIC,
+    // looping the server route back into the tunnel it's meant to bypass.
+    wifi_iface: String,
 }
 
 impl MacOsNetManager {
@@ -42,13 +48,18 @@ impl MacOsNetManager {
             server_host,
             original_gateway,
             primary_service,
+            wifi_iface: iface,
         })
     }
 
     // Always adds split-default (0/1 + 128/1) for full-tunnel mode.
     // Split-tunnel (per-route from ServerConfig) is not yet supported on macOS.
     pub async fn setup_vpn_routes(&self) -> Result<()> {
-        run("route", &["add", "-host", &self.server_host, &self.original_gateway]).await;
+        run(
+            "route",
+            &["add", "-host", &self.server_host, &self.original_gateway, "-ifscope", &self.wifi_iface],
+        )
+        .await;
         run("route", &["add", "-net", "0.0.0.0/1", "-interface", &self.tun_name]).await;
         run("route", &["add", "-net", "128.0.0.0/1", "-interface", &self.tun_name]).await;
         info!("macOS VPN routes added via {}", self.tun_name);
@@ -89,7 +100,11 @@ impl MacOsNetManager {
     // the wrong gateway until the next reconnect that creates a new MacOsNetManager.
     pub async fn ensure_server_route(&self) -> Result<()> {
         run("route", &["delete", "-host", &self.server_host]).await;
-        run("route", &["add", "-host", &self.server_host, &self.original_gateway]).await;
+        run(
+            "route",
+            &["add", "-host", &self.server_host, &self.original_gateway, "-ifscope", &self.wifi_iface],
+        )
+        .await;
         Ok(())
     }
 

konduit-platform/src/routes/windows.rs

@@ -13,6 +13,12 @@ pub struct RouteManager {
     tun_routes: Vec<(Ipv4Addr, u8)>,
     server_ip: Option<Ipv4Addr>,
     wifi_gateway: Option<Ipv4Addr>,
+    // Physical interface name the server host route must be pinned to. Without
+    // this, if the VPN's assigned tun subnet happens to contain the physical
+    // gateway IP, `route add`'s gateway-only resolution can pick the tun
+    // interface instead of the physical NIC, looping the server route back
+    // into the tunnel it's meant to bypass.
+    wifi_iface: Option<String>,
 }
 
 impl RouteManager {
@@ -27,17 +33,23 @@ impl RouteManager {
             tun_routes: Vec::new(),
             server_ip: None,
             wifi_gateway: None,
+            wifi_iface: None,
         })
     }
 
-    fn get_default_gateway() -> Result<Ipv4Addr> {
+    /// Returns the physical default gateway and the friendly name of the
+    /// adapter it's reachable on. The interface name must be used to pin any
+    /// route meant to bypass the tunnel — relying on gateway-only resolution
+    /// lets `route add` route it via the TUN adapter instead if the VPN's
+    /// assigned subnet happens to contain this gateway IP.
+    fn get_default_gateway() -> Result<(Ipv4Addr, String)> {
         let adapters = ipconfig::get_adapters()
             .map_err(|e| anyhow::anyhow!("Failed to enumerate adapters: {}", e))?;
         for adapter in &adapters {
             for gw in adapter.gateways() {
                 if let IpAddr::V4(gw4) = gw {
                     if !gw4.is_loopback() && !gw4.is_unspecified() {
-                        return Ok(*gw4);
+                        return Ok((*gw4, adapter.friendly_name().to_string()));
                     }
                 }
             }
@@ -45,29 +57,26 @@ impl RouteManager {
         anyhow::bail!("No default gateway found")
     }
 
-    fn prefix_to_mask(prefix: u8) -> Ipv4Addr {
+    // Add/delete the server host route through the physical WiFi/Ethernet
-        let bits = if prefix == 0 {
+    // interface, pinned explicitly by adapter name via `netsh` rather than
-            0u32
+    // `route add`'s gateway-only resolution — same rationale and technique as
-        } else {
+    // `tun_route_add` below: without an explicit interface, an IP collision
-            !0u32 << (32 - prefix)
+    // between the VPN's assigned tun subnet and the physical gateway can make
-        };
+    // this route resolve onto the TUN adapter instead, looping the server
-        let [a, b, c, d] = bits.to_be_bytes();
+    // route back into the tunnel it's meant to bypass.
-        Ipv4Addr::new(a, b, c, d)
+    fn wifi_route_add(iface: &str, dest: Ipv4Addr, prefix: u8, gateway: Ipv4Addr) {
-    }
+        let prefix_str = format!("{}/{}", dest, prefix);
-
+        let out = std::process::Command::new("netsh")
-    // Add/delete server host route through WiFi gateway via `route` command.
-    // Specifying gateway on delete ensures we only remove our entry, not any other path.
-    fn wifi_route_add(dest: Ipv4Addr, prefix: u8, gateway: Ipv4Addr) {
-        let mask = Self::prefix_to_mask(prefix);
-        let out = std::process::Command::new("route")
             .args([
+                "interface",
+                "ipv4",
                 "add",
-                &dest.to_string(),
+                "route",
-                "MASK",
+                &prefix_str,
-                &mask.to_string(),
+                iface,
-                &gateway.to_string(),
+                &format!("nexthop={}", gateway),
-                "METRIC",
+                "metric=1",
-                "1",
+                "store=active",
             ])
             .creation_flags(CREATE_NO_WINDOW)
             .output();
@@ -76,25 +85,19 @@ impl RouteManager {
                 let stdout = String::from_utf8_lossy(&o.stdout);
                 if !o.status.success() {
                     // "already exists" is acceptable — a previous run may have left it
-                    warn!("route add {}/{} via {}: {}", dest, prefix, gateway, stdout.trim());
+                    warn!("netsh add route {}/{} via {} on {}: {}", dest, prefix, gateway, iface, stdout.trim());
                 }
             }
-            Err(e) => warn!("route add {}/{} via {}: {}", dest, prefix, gateway, e),
+            Err(e) => warn!("netsh add route {}/{} via {} on {}: {}", dest, prefix, gateway, iface, e),
         }
     }
 
-    fn wifi_route_delete(dest: Ipv4Addr, prefix: u8, gateway: Ipv4Addr) {
+    fn wifi_route_delete(iface: &str, dest: Ipv4Addr, prefix: u8) {
-        let mask = Self::prefix_to_mask(prefix);
+        let prefix_str = format!("{}/{}", dest, prefix);
-        let _ = std::process::Command::new("route")
+        let _ = std::process::Command::new("netsh")
-            .args([
+            .args(["interface", "ipv4", "delete", "route", &prefix_str, iface])
-                "delete",
-                &dest.to_string(),
-                "MASK",
-                &mask.to_string(),
-                &gateway.to_string(),
-            ])
             .creation_flags(CREATE_NO_WINDOW)
-            .status();
+            .output();
     }
 
     // Add/delete routes through the TUN interface using netsh.
@@ -169,8 +172,9 @@ impl RouteManager {
     ) -> Result<()> {
         info!("Setting up Windows VPN routes...");
 
-        let current_gateway = Self::get_default_gateway()?;
+        let (current_gateway, wifi_iface) = Self::get_default_gateway()?;
-        info!("Current gateway: {}", current_gateway);
+        info!("Current gateway: {} (interface {})", current_gateway, wifi_iface);
+        self.wifi_iface = Some(wifi_iface.clone());
 
         let server_ip: Ipv4Addr = {
             let host = server_addr.split(':').next().unwrap_or(server_addr);
@@ -189,7 +193,7 @@ impl RouteManager {
         // even if the add below fails because the route already exists.
         self.server_ip = Some(server_ip);
         self.wifi_gateway = Some(current_gateway);
-        Self::wifi_route_add(server_ip, 32, current_gateway);
+        Self::wifi_route_add(&wifi_iface, server_ip, 32, current_gateway);
 
         let is_full_tunnel = routes.iter().any(|r| r == "0.0.0.0/0");
 
@@ -242,8 +246,10 @@ impl RouteManager {
     }
 
     pub async fn ensure_server_route(&mut self) -> Result<()> {
-        if let (Some(server_ip), Some(gateway)) = (self.server_ip, self.wifi_gateway) {
+        if let (Some(server_ip), Some(gateway), Some(iface)) =
-            Self::wifi_route_add(server_ip, 32, gateway);
+            (self.server_ip, self.wifi_gateway, self.wifi_iface.as_deref())
+        {
+            Self::wifi_route_add(iface, server_ip, 32, gateway);
         }
         Ok(())
     }
@@ -280,8 +286,9 @@ impl RouteManager {
         }
         // Always clean up the server host route — a previous unclean exit may have
         // left it behind even if our add was skipped.
-        if let (Some(server_ip), Some(gateway)) = (self.server_ip.take(), self.wifi_gateway.take()) {
+        self.wifi_gateway.take();
-            Self::wifi_route_delete(server_ip, 32, gateway);
+        if let (Some(server_ip), Some(iface)) = (self.server_ip.take(), self.wifi_iface.take()) {
+            Self::wifi_route_delete(&iface, server_ip, 32);
         }
         info!("Windows VPN routes removed");
         Ok(())