diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf93e66..a3c6b49 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,6 +40,7 @@
 1. pdr: Return success for pldm_pdr_find_child_container_id_range_exclude() API
 2. pdr: Rework pldm_pdr_find_container_id_range_exclude() API
 3. transport: mctp-demux: Don't test socket for non-zero value
+4. requester: Return PLDM_REQUESTER_OPEN_FAIL from pldm_open() on error
 
 ## [0.3.0] - 2023-06-23
 
diff --git a/src/requester/pldm.c b/src/requester/pldm.c
index 8fd5d38..0c28b31 100644
--- a/src/requester/pldm.c
+++ b/src/requester/pldm.c
@@ -3,6 +3,7 @@
 #include "libpldm/transport.h"
 
 #include <bits/types/struct_iovec.h>
+#include <fcntl.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,24 +29,31 @@
 LIBPLDM_ABI_STABLE
 pldm_requester_rc_t pldm_open(void)
 {
-	int fd;
-	int rc;
+	int fd = PLDM_REQUESTER_OPEN_FAIL;
 
 	if (open_transport) {
 		fd = pldm_transport_mctp_demux_get_socket_fd(open_transport);
-		return fd;
+
+		/* If someone has externally issued close() on fd then we need to start again. Use
+		 * `fcntl(..., F_GETFD)` to test whether fd is valid. */
+		if (fd < 0 || fcntl(fd, F_GETFD) < 0) {
+			pldm_close();
+		}
 	}
 
-	struct pldm_transport_mctp_demux *demux = NULL;
-	rc = pldm_transport_mctp_demux_init(&demux);
-	if (rc) {
-		return rc;
+	/* We retest open_transport as it may have been set to NULL by pldm_close() above. */
+	if (!open_transport) {
+		struct pldm_transport_mctp_demux *demux = NULL;
+
+		if (pldm_transport_mctp_demux_init(&demux) < 0) {
+			return PLDM_REQUESTER_OPEN_FAIL;
+		}
+
+		open_transport = demux;
+
+		fd = pldm_transport_mctp_demux_get_socket_fd(open_transport);
 	}
 
-	fd = pldm_transport_mctp_demux_get_socket_fd(demux);
-
-	open_transport = demux;
-
 	return fd;
 }