diff --git a/README.md b/README.md
index bb62e1b..3b8ae9e 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,7 @@ Windows route-table boundary:
 - selected source address, next hop, interface index/LUID, prefix, and metric
 - interface index/LUID lookup from Windows network adapter GUIDs
 - scoped IP interface metric overrides with restore-on-drop behavior
+- scoped default-route suppression with restore-on-drop behavior
 - scoped host-route pinning for the relay IP on the pre-TAP interface
 - non-Windows builds return a clear unsupported-platform error
 
diff --git a/crates/lanparty-client-route/src/lib.rs b/crates/lanparty-client-route/src/lib.rs
index 718a3af..cefdb7a 100644
--- a/crates/lanparty-client-route/src/lib.rs
+++ b/crates/lanparty-client-route/src/lib.rs
@@ -2,7 +2,7 @@
 //!
 //! The client binary uses this crate to keep Win32 route/metric calls out of
 //! the relay session code. The crate can snapshot the current relay route and
-//! install a scoped host route that pins the relay IP to the pre-TAP interface.
+//! install scoped route/interface overrides that are restored when dropped.
 
 use std::net::IpAddr;
 
@@ -175,7 +175,10 @@ mod windows;
 #[cfg(windows)]
 pub use windows::{PinnedRelayRoute, best_route_to, interface_identity_from_guid, pin_relay_route};
 #[cfg(windows)]
-pub use windows::{ScopedInterfaceMetric, interface_metric, set_scoped_interface_metric};
+pub use windows::{
+    ScopedDefaultRoutes, ScopedInterfaceMetric, interface_metric,
+    set_scoped_default_routes_disabled, set_scoped_interface_metric,
+};
 
 #[cfg(not(windows))]
 pub fn best_route_to(_destination: IpAddr) -> Result<RouteSnapshot> {
@@ -221,6 +224,21 @@ pub fn set_scoped_interface_metric(
     bail!("Windows interface metric updates are only available on Windows");
 }
 
+#[cfg(not(windows))]
+#[derive(Debug)]
+pub struct ScopedDefaultRoutes {
+    _private: (),
+}
+
+#[cfg(not(windows))]
+pub fn set_scoped_default_routes_disabled(
+    _identity: NetworkInterfaceIdentity,
+    _family: IpInterfaceFamily,
+    _disabled: bool,
+) -> Result<ScopedDefaultRoutes> {
+    bail!("Windows interface default-route updates are only available on Windows");
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -305,6 +323,9 @@ mod tests {
 
         assert!(interface_metric(identity, IpInterfaceFamily::Ipv4).is_err());
         assert!(set_scoped_interface_metric(identity, IpInterfaceFamily::Ipv4, 500).is_err());
+        assert!(
+            set_scoped_default_routes_disabled(identity, IpInterfaceFamily::Ipv4, true).is_err()
+        );
     }
 
     fn ip(value: &str) -> IpAddr {
diff --git a/crates/lanparty-client-route/src/windows.rs b/crates/lanparty-client-route/src/windows.rs
index ea5a026..8728496 100644
--- a/crates/lanparty-client-route/src/windows.rs
+++ b/crates/lanparty-client-route/src/windows.rs
@@ -78,6 +78,24 @@ pub fn set_scoped_interface_metric(
     })
 }
 
+pub fn set_scoped_default_routes_disabled(
+    identity: NetworkInterfaceIdentity,
+    family: IpInterfaceFamily,
+    disabled: bool,
+) -> Result<ScopedDefaultRoutes> {
+    let previous = interface_metric(identity, family)?;
+    let mut row = get_interface_row(identity, family)?;
+    row.DisableDefaultRoutes = disabled;
+    set_interface_row(&mut row).with_context(|| {
+        format!("failed to set {family:?} default-route disabled state to {disabled}")
+    })?;
+
+    Ok(ScopedDefaultRoutes {
+        previous,
+        active: true,
+    })
+}
+
 pub struct ScopedInterfaceMetric {
     previous: InterfaceMetricSnapshot,
     active: bool,
@@ -109,6 +127,37 @@ impl Drop for ScopedInterfaceMetric {
     }
 }
 
+pub struct ScopedDefaultRoutes {
+    previous: InterfaceMetricSnapshot,
+    active: bool,
+}
+
+impl ScopedDefaultRoutes {
+    #[must_use]
+    pub const fn previous(&self) -> InterfaceMetricSnapshot {
+        self.previous
+    }
+}
+
+impl fmt::Debug for ScopedDefaultRoutes {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("ScopedDefaultRoutes")
+            .field("previous", &self.previous)
+            .field("active", &self.active)
+            .finish()
+    }
+}
+
+impl Drop for ScopedDefaultRoutes {
+    fn drop(&mut self) {
+        if !self.active {
+            return;
+        }
+
+        let _ = restore_default_routes(self.previous);
+    }
+}
+
 pub fn best_route_to(destination: IpAddr) -> Result<RouteSnapshot> {
     let destination_sockaddr = sockaddr_from_ip(destination);
     let mut route = MIB_IPFORWARD_ROW2::default();
@@ -183,6 +232,12 @@ fn restore_interface_metric(snapshot: InterfaceMetricSnapshot) -> Result<()> {
     set_interface_row(&mut row)
 }
 
+fn restore_default_routes(snapshot: InterfaceMetricSnapshot) -> Result<()> {
+    let mut row = get_interface_row(snapshot.identity(), snapshot.family())?;
+    row.DisableDefaultRoutes = snapshot.disable_default_routes();
+    set_interface_row(&mut row)
+}
+
 fn interface_row_key(
     identity: NetworkInterfaceIdentity,
     family: IpInterfaceFamily,