diff --git a/scripts/dev.mjs b/scripts/dev.mjs
index 62afc41..2964f68 100755
--- a/scripts/dev.mjs
+++ b/scripts/dev.mjs
@@ -52,6 +52,11 @@ function freePort(port) {
   } catch {
     // port already free
   }
+  try {
+    execSync(`lsof -ti UDP:${port} | xargs kill -9`, { stdio: 'ignore' });
+  } catch {
+    // port already free
+  }
 }
 
 function spawnChild(command, args, label, cwd = root, extraEnv = {}) {