diff --git a/src/misc/socket.cc b/src/misc/socket.cc
index 56c96c5359..037d1ff687 100644
--- a/src/misc/socket.cc
+++ b/src/misc/socket.cc
@@ -818,7 +818,14 @@ ncclResult_t ncclSocketTryRecv(struct ncclSocket* sock, void* ptr, int size, int
 
 ncclResult_t ncclSocketClose(struct ncclSocket* sock) {
   if (sock != NULL) {
-    if (sock->fd >= 0) close(sock->fd);
+    if (sock->fd >= 0) {
+      /* shutdown() is needed to send FIN packet to proxy thread; shutdown() is not affected
+       * by refcount of fd, but close() is. close() won't close a fd and send FIN packet if
+       * the fd is duplicated (e.g. fork()). So shutdown() guarantees the correct and graceful
+       * connection close here. */
+      shutdown(sock->fd, SHUT_RDWR);
+      close(sock->fd);
+    }
     sock->state = ncclSocketStateClosed;
     sock->fd = -1;
   }