diff --git a/gns3server/compute/docker/docker_vm.py b/gns3server/compute/docker/docker_vm.py
index 63ca5a089..2c95b23ee 100644
--- a/gns3server/compute/docker/docker_vm.py
+++ b/gns3server/compute/docker/docker_vm.py
@@ -1959,6 +1959,13 @@ class DockerVM(BaseNode):
         if host_ifc is not None and bridge_name not in self._bridges:
             await self._ubridge_send(f"bridge create {bridge_name}")
             self._bridges.add(bridge_name)
+            # libpcap cannot open a packet socket on an admin-down interface
+            # (its netlink promiscuous-mode transaction returns ENOENT), and
+            # the unified veth host end is born down (carrier off until a
+            # link attaches) — bring it up for the relay attach. The carrier
+            # pass in the caller refines the state afterwards (a suspended
+            # NIO sets it back down).
+            await self._ubridge_send(f'link set "{host_ifc}" up')
             await self._ubridge_send(f'bridge add_nio_ethernet {bridge_name} "{host_ifc}"')
         await self._ubridge_send(
             "bridge add_nio_udp {bridge_name} {lport} {rhost} {rport}".format(
diff --git a/tests/compute/docker/test_docker_kernel_datapath.py b/tests/compute/docker/test_docker_kernel_datapath.py
index a467a21c9..6cf1f2ca1 100644
--- a/tests/compute/docker/test_docker_kernel_datapath.py
+++ b/tests/compute/docker/test_docker_kernel_datapath.py
@@ -222,6 +222,9 @@ async def test_add_ubridge_connection_udp_relays_over_veth(vm):
         [
             call.send(f'docker create_veth "{host_ifc}" "{vm._veth_names(0, 0)[1]}"'),
             call.send("bridge create bridge0"),
+            # the host end is born down; libpcap cannot attach to an
+            # admin-down interface, so the relay brings it up first
+            call.send(f'link set "{host_ifc}" up'),
             call.send(f'bridge add_nio_ethernet bridge0 "{host_ifc}"'),
             call.send("bridge add_nio_udp bridge0 4242 127.0.0.1 4343"),
             call.send("bridge start bridge0"),