diff --git a/src/main.rs b/src/main.rs
index 384e120..4efe3a9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -180,6 +180,10 @@ impl file_rpc::Server for Serv {
     fn size(&self, _fd: u64) -> Option<u64> {
         None
     }
+    
+    fn dup(&self, fd: u64) -> Option<u64> {
+        Some(fd)
+    }
 }
 
 fn main() {