diff -Naur libreswan-3.25-orig/include/pluto_constants.h libreswan-3.25/include/pluto_constants.h
--- libreswan-3.25-orig/include/pluto_constants.h	2018-06-27 11:42:26.000000000 -0400
+++ libreswan-3.25/include/pluto_constants.h	2019-02-23 20:46:36.030789127 -0500
@@ -421,6 +421,7 @@
 	IMPAIR_REPLAY_DUPLICATES_IX,		/* replay duplicates of each incoming packet */
 	IMPAIR_REPLAY_FORWARD_IX,		/* replay all earlier packets old-to-new */
 	IMPAIR_REPLAY_BACKWARD_IX,		/* replay all earlier packets new-to-old */
+	IMPAIR_IKEv1_DEL_WITH_NOTIFY_IX,	/* causes pluto send send IKE Delete with additional bogus Notify */
 
 	IMPAIR_REPLAY_ENCRYPTED_IX,		/* replay encrypted packets */
 	IMPAIR_CORRUPT_ENCRYPTED_IX,		/* corrupts the encrypted packet so that the decryption fails */
@@ -480,6 +481,7 @@
 #define IMPAIR_REPLAY_DUPLICATES 	LELEM(IMPAIR_REPLAY_DUPLICATES_IX)
 #define IMPAIR_REPLAY_FORWARD	 	LELEM(IMPAIR_REPLAY_FORWARD_IX)
 #define IMPAIR_REPLAY_BACKWARD 		LELEM(IMPAIR_REPLAY_BACKWARD_IX)
+#define IMPAIR_IKEv1_DEL_WITH_NOTIFY 	LELEM(IMPAIR_IKEv1_DEL_WITH_NOTIFY_IX)
 
 #define IMPAIR_REPLAY_ENCRYPTED			LELEM(IMPAIR_REPLAY_ENCRYPTED_IX)
 #define IMPAIR_CORRUPT_ENCRYPTED		LELEM(IMPAIR_CORRUPT_ENCRYPTED_IX)
diff -Naur libreswan-3.25-orig/lib/libswan/impair.c libreswan-3.25/lib/libswan/impair.c
--- libreswan-3.25-orig/lib/libswan/impair.c	2018-06-27 11:42:26.000000000 -0400
+++ libreswan-3.25/lib/libswan/impair.c	2019-02-23 20:47:28.556333015 -0500
@@ -61,6 +61,7 @@
 	I(IMPAIR_REPLAY_DUPLICATES, "impair-replay-duplicates"),
 	I(IMPAIR_REPLAY_FORWARD, "impair-replay-forward"),
 	I(IMPAIR_REPLAY_BACKWARD, "impair-replay-backward"),
+	I(IMPAIR_IKEv1_DEL_WITH_NOTIFY, "impair-ikev1-del-with-notify"),
 
 	I(IMPAIR_REPLAY_ENCRYPTED, "impair-replay-encrypted"),
 	I(IMPAIR_CORRUPT_ENCRYPTED, "impair-corrupt-encrypted"),
diff -Naur libreswan-3.25-orig/programs/pluto/ikev1_main.c libreswan-3.25/programs/pluto/ikev1_main.c
--- libreswan-3.25-orig/programs/pluto/ikev1_main.c	2018-06-27 11:42:26.000000000 -0400
+++ libreswan-3.25/programs/pluto/ikev1_main.c	2019-02-23 20:44:30.295457365 -0500
@@ -2489,14 +2489,36 @@
 				said ? ISAKMP_NEXT_NONE : ISAKMP_NEXT_D;
 			isad.isad_spisize = sizeof(ipsec_spi_t);
 			isad.isad_protoid = ns->proto;
-
 			isad.isad_nospi = 1;
+
+			if (DBGP(IMPAIR_IKEv1_DEL_WITH_NOTIFY))
+				isad.isad_np = ISAKMP_NEXT_N; /* Notify */
+
 			passert(out_struct(&isad, &isakmp_delete_desc, &r_hdr_pbs,
 					   &del_pbs));
 			passert(out_raw(&ns->spi, sizeof(ipsec_spi_t),
 					&del_pbs,
 					"delete payload"));
 			close_output_pbs(&del_pbs);
+
+			if (DBGP(IMPAIR_IKEv1_DEL_WITH_NOTIFY)) {
+				pb_stream cruft_pbs;
+
+				libreswan_log("IMPAIR: adding bogus Notify payload after IKE Delete payload");
+				struct isakmp_notification isan = {
+					.isan_np = ISAKMP_NEXT_NONE,
+					.isan_doi = ISAKMP_DOI_IPSEC,
+					.isan_protoid = PROTO_ISAKMP,
+					.isan_spisize = COOKIE_SIZE * 2,
+					.isan_type = INVALID_PAYLOAD_TYPE,
+				};
+
+				passert(out_struct(&isan, &isakmp_notification_desc, &r_hdr_pbs,
+					&cruft_pbs));
+				passert(out_raw(&ns->spi, sizeof(ipsec_spi_t), &cruft_pbs,
+					"notify payload"));
+				close_output_pbs(&cruft_pbs);
+			}
 		}
 	}
 
@@ -2743,7 +2765,9 @@
 					rc->policy &= ~POLICY_UP;
 					if (!shared_phase1_connection(rc)) {
 						flush_pending_by_connection(rc);
+						/* This also deletes the IKE SA, clear pointer  */
 						delete_states_by_connection(rc, FALSE);
+						md->st = NULL;
 					}
 					reset_cur_connection();
 				}