diff --git a/src/libcharon/config/proposal.c b/src/libcharon/config/proposal.c
index ddbc155c3..011c0b8b0 100644
--- a/src/libcharon/config/proposal.c
+++ b/src/libcharon/config/proposal.c
@@ -419,25 +419,41 @@ static const struct {
 	{AUTH_AES_CMAC_96,					PRF_AES128_CMAC					},
 };
 
+/**
+ * Remove all entries of the given transform type
+ */
+static void remove_transform(private_proposal_t *this, transform_type_t type)
+{
+	enumerator_t *e;
+	entry_t *entry;
+
+	e = array_create_enumerator(this->transforms);
+	while (e->enumerate(e, &entry))
+	{
+		if (entry->type == type)
+		{
+			array_remove_at(this->transforms, e);
+		}
+	}
+	e->destroy(e);
+}
+
 /**
  * Checks the proposal read from a string.
  */
-static void check_proposal(private_proposal_t *this)
+static bool check_proposal(private_proposal_t *this)
 {
 	enumerator_t *e;
 	entry_t *entry;
 	uint16_t alg, ks;
-	bool all_aead = TRUE;
+	bool all_aead = TRUE, any_aead = FALSE, any_enc = FALSE;
 	int i;
 
 	if (this->protocol == PROTO_IKE)
 	{
-		e = create_enumerator(this, PSEUDO_RANDOM_FUNCTION);
-		if (!e->enumerate(e, &alg, &ks))
-		{
-			/* No explicit PRF found. We assume the same algorithm as used
-			 * for integrity checking */
-			e->destroy(e);
+		if (!get_algorithm(this, PSEUDO_RANDOM_FUNCTION, NULL, NULL))
+		{	/* No explicit PRF found. We assume the same algorithm as used
+			 * for integrity checking. */
 			e = create_enumerator(this, INTEGRITY_ALGORITHM);
 			while (e->enumerate(e, &alg, &ks))
 			{
@@ -451,8 +467,13 @@ static void check_proposal(private_proposal_t *this)
 					}
 				}
 			}
+			e->destroy(e);
+		}
+		if (!get_algorithm(this, PSEUDO_RANDOM_FUNCTION, NULL, NULL))
+		{
+			DBG1(DBG_CFG, "a PRF algorithm is mandatory in IKE proposals");
+			return FALSE;
 		}
-		e->destroy(e);
 		/* remove MODP_NONE from IKE proposal */
 		e = array_create_enumerator(this->transforms);
 		while (e->enumerate(e, &entry))
@@ -463,48 +484,103 @@ static void check_proposal(private_proposal_t *this)
 			}
 		}
 		e->destroy(e);
+		if (!get_algorithm(this, DIFFIE_HELLMAN_GROUP, NULL, NULL))
+		{
+			DBG1(DBG_CFG, "a DH group is mandatory in IKE proposals");
+			return FALSE;
+		}
+	}
+	else
+	{	/* remove PRFs from ESP/AH proposals */
+		remove_transform(this, PSEUDO_RANDOM_FUNCTION);
 	}
 
-	if (this->protocol == PROTO_ESP)
+	if (this->protocol == PROTO_IKE || this->protocol == PROTO_ESP)
 	{
 		e = create_enumerator(this, ENCRYPTION_ALGORITHM);
 		while (e->enumerate(e, &alg, &ks))
 		{
-			if (!encryption_algorithm_is_aead(alg))
+			any_enc = TRUE;
+			if (encryption_algorithm_is_aead(alg))
 			{
-				all_aead = FALSE;
-				break;
+				any_aead = TRUE;
+				continue;
+			}
+			all_aead = FALSE;
+		}
+		e->destroy(e);
+
+		if (!any_enc)
+		{
+			DBG1(DBG_CFG, "an encryption algorithm is mandatory in %N proposals",
+				 protocol_id_names, this->protocol);
+			return FALSE;
+		}
+		else if (any_aead && !all_aead)
+		{
+			DBG1(DBG_CFG, "classic and combined-mode (AEAD) encryption "
+				 "algorithms can't be contained in the same %N proposal",
+				 protocol_id_names, this->protocol);
+			return FALSE;
+		}
+		else if (all_aead)
+		{	/* if all encryption algorithms in the proposal are AEADs,
+			 * we MUST NOT propose any integrity algorithms */
+			remove_transform(this, INTEGRITY_ALGORITHM);
+		}
+	}
+	else
+	{	/* AES-GMAC is parsed as encryption algorithm, so we map that to the
+		 * proper integrity algorithm */
+		e = array_create_enumerator(this->transforms);
+		while (e->enumerate(e, &entry))
+		{
+			if (entry->type == ENCRYPTION_ALGORITHM)
+			{
+				if (entry->alg == ENCR_NULL_AUTH_AES_GMAC)
+				{
+					entry->type = INTEGRITY_ALGORITHM;
+					ks = entry->key_size;
+					entry->key_size = 0;
+					switch (ks)
+					{
+						case 128:
+							entry->alg = AUTH_AES_128_GMAC;
+							continue;
+						case 192:
+							entry->alg = AUTH_AES_192_GMAC;
+							continue;
+						case 256:
+							entry->alg = AUTH_AES_256_GMAC;
+							continue;
+						default:
+							break;
+					}
+				}
+				/* remove all other encryption algorithms */
+				array_remove_at(this->transforms, e);
 			}
 		}
 		e->destroy(e);
 
-		if (all_aead)
+		if (!get_algorithm(this, INTEGRITY_ALGORITHM, NULL, NULL))
 		{
-			/* if all encryption algorithms in the proposal are AEADs,
-			 * we MUST NOT propose any integrity algorithms */
-			e = array_create_enumerator(this->transforms);
-			while (e->enumerate(e, &entry))
-			{
-				if (entry->type == INTEGRITY_ALGORITHM)
-				{
-					array_remove_at(this->transforms, e);
-				}
-			}
-			e->destroy(e);
+			DBG1(DBG_CFG, "an integrity algorithm is mandatory in AH "
+				 "proposals");
+			return FALSE;
 		}
 	}
 
 	if (this->protocol == PROTO_AH || this->protocol == PROTO_ESP)
 	{
-		e = create_enumerator(this, EXTENDED_SEQUENCE_NUMBERS);
-		if (!e->enumerate(e, NULL, NULL))
+		if (!get_algorithm(this, EXTENDED_SEQUENCE_NUMBERS, NULL, NULL))
 		{	/* ESN not specified, assume not supported */
 			add_algorithm(this, EXTENDED_SEQUENCE_NUMBERS, NO_EXT_SEQ_NUMBERS, 0);
 		}
-		e->destroy(e);
 	}
 
 	array_compress(this->transforms);
+	return TRUE;
 }
 
 /**
@@ -1000,13 +1076,11 @@ proposal_t *proposal_create_from_string(protocol_id_t protocol, const char *algs
 	}
 	enumerator->destroy(enumerator);
 
-	if (failed)
+	if (failed || !check_proposal(this))
 	{
 		destroy(this);
 		return NULL;
 	}
 
-	check_proposal(this);
-
 	return &this->public;
 }
diff --git a/src/libcharon/sa/ikev2/tasks/ike_init.c b/src/libcharon/sa/ikev2/tasks/ike_init.c
index 92909cff8..d82e206b8 100644
--- a/src/libcharon/sa/ikev2/tasks/ike_init.c
+++ b/src/libcharon/sa/ikev2/tasks/ike_init.c
@@ -655,6 +655,7 @@ METHOD(task_t, build_r, status_t,
 		else
 		{
 			DBG1(DBG_IKE, "no acceptable proposal found");
+			message->add_notify(message, TRUE, NO_PROPOSAL_CHOSEN, chunk_empty);
 		}
 		return FAILED;
 	}
diff --git a/src/libcharon/tests/libcharon_tests.c b/src/libcharon/tests/libcharon_tests.c
index e25e5434f..1ef13e978 100644
--- a/src/libcharon/tests/libcharon_tests.c
+++ b/src/libcharon/tests/libcharon_tests.c
@@ -32,6 +32,22 @@ static test_configuration_t tests[] = {
 	{ .suite = NULL, }
 };
 
+static void initialize_logging()
+{
+	int level = LEVEL_SILENT;
+	char *verbosity;
+
+	verbosity = getenv("TESTS_VERBOSITY");
+	if (verbosity)
+	{
+		level = atoi(verbosity);
+	}
+	lib->settings->set_int(lib->settings, "%s.filelog.stderr.default",
+			lib->settings->get_int(lib->settings, "%s.filelog.stderr.default",
+								   level, lib->ns), lib->ns);
+	charon->load_loggers(charon, NULL, TRUE);
+}
+
 static bool test_runner_init(bool init)
 {
 	if (init)
@@ -39,6 +55,7 @@ static bool test_runner_init(bool init)
 		char *plugins, *plugindir;
 
 		libcharon_init();
+		initialize_logging();
 
 		plugins = getenv("TESTS_PLUGINS") ?:
 					lib->settings->get_str(lib->settings,
diff --git a/src/libcharon/tests/suites/test_proposal.c b/src/libcharon/tests/suites/test_proposal.c
index a6226f68f..19f4cd1e1 100644
--- a/src/libcharon/tests/suites/test_proposal.c
+++ b/src/libcharon/tests/suites/test_proposal.c
@@ -18,38 +18,100 @@
 #include <config/proposal.h>
 
 static struct {
+	protocol_id_t proto;
+	char *proposal;
+	char *expected;
+} create_data[] = {
+	{ PROTO_IKE, "", NULL },
+	{ PROTO_IKE, "sha256", NULL },
+	{ PROTO_IKE, "sha256-modp3072", NULL },
+	{ PROTO_IKE, "null-sha256-modp3072", "IKE:NULL/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_3072" },
+	{ PROTO_IKE, "aes128", NULL },
+	{ PROTO_IKE, "aes128-sha256", NULL },
+	{ PROTO_IKE, "aes128-sha256-modpnone", NULL },
+	{ PROTO_IKE, "aes128-sha256-modp3072", "IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_3072" },
+	{ PROTO_IKE, "aes128-sha256-prfsha384-modp3072", "IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_384/MODP_3072" },
+	{ PROTO_IKE, "aes128gcm16-modp3072", NULL },
+	{ PROTO_IKE, "aes128gcm16-prfsha256-modp3072", "IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_3072" },
+	{ PROTO_IKE, "aes128gcm16-sha256-modp3072", "IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_3072" },
+	{ PROTO_IKE, "aes128gcm16-aes128-modp3072", NULL },
+	{ PROTO_IKE, "aes128gcm16-aes128-sha256-modp3072", NULL },
+	{ PROTO_ESP, "", NULL },
+	{ PROTO_ESP, "sha256", NULL },
+	{ PROTO_ESP, "aes128-sha256", "ESP:AES_CBC_128/HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_ESP, "aes128-sha256-esn", "ESP:AES_CBC_128/HMAC_SHA2_256_128/EXT_SEQ" },
+	{ PROTO_ESP, "aes128-sha256-noesn", "ESP:AES_CBC_128/HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_ESP, "aes128-sha256-esn-noesn", "ESP:AES_CBC_128/HMAC_SHA2_256_128/EXT_SEQ/NO_EXT_SEQ" },
+	{ PROTO_ESP, "aes128-sha256-prfsha256-modp3072", "ESP:AES_CBC_128/HMAC_SHA2_256_128/MODP_3072/NO_EXT_SEQ" },
+	{ PROTO_ESP, "aes128gcm16-aes128-sha256-modp3072", NULL },
+	{ PROTO_ESP, "aes128gmac", "ESP:NULL_AES_GMAC_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "", NULL },
+	{ PROTO_AH,  "aes128", NULL },
+	{ PROTO_AH,  "aes128-sha256", "AH:HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "sha256-sha1", "AH:HMAC_SHA2_256_128/HMAC_SHA1_96/NO_EXT_SEQ" },
+	{ PROTO_AH,  "aes128gmac-sha256", "AH:AES_128_GMAC/HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "aes128gmac-sha256-prfsha256", "AH:AES_128_GMAC/HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "aes128gmac-aes256gmac-aes128-sha256", "AH:AES_128_GMAC/AES_256_GMAC/HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "sha256-esn", "AH:HMAC_SHA2_256_128/EXT_SEQ" },
+	{ PROTO_AH,  "sha256-noesn", "AH:HMAC_SHA2_256_128/NO_EXT_SEQ" },
+	{ PROTO_AH,  "sha256-esn-noesn", "AH:HMAC_SHA2_256_128/EXT_SEQ/NO_EXT_SEQ" },
+};
+
+START_TEST(test_create_from_string)
+{
+	proposal_t *proposal;
+	char str[BUF_LEN];
+
+	proposal = proposal_create_from_string(create_data[_i].proto,
+										   create_data[_i].proposal);
+	if (!create_data[_i].expected)
+	{
+		ck_assert(!proposal);
+		return;
+	}
+	snprintf(str, sizeof(str), "%P", proposal);
+	ck_assert_str_eq(create_data[_i].expected, str);
+	proposal->destroy(proposal);
+}
+END_TEST
+
+static struct {
+	protocol_id_t proto;
 	char *self;
 	char *other;
 	char *expected;
 } select_data[] = {
-	{ "aes128", "aes128", "aes128" },
-	{ "aes128", "aes256", NULL },
-	{ "aes128-aes256", "aes256-aes128", "aes128" },
-	{ "aes256-aes128", "aes128-aes256", "aes256" },
-	{ "aes128-aes256-sha1-sha256", "aes256-aes128-sha256-sha1", "aes128-sha1" },
-	{ "aes256-aes128-sha256-sha1", "aes128-aes256-sha1-sha256", "aes256-sha256" },
-	{ "aes128-sha256-modp3072", "aes128-sha256", NULL },
-	{ "aes128-sha256", "aes128-sha256-modp3072", NULL },
-	{ "aes128-sha256-modp3072", "aes128-sha256-modpnone", NULL },
-	{ "aes128-sha256-modpnone", "aes128-sha256-modp3072", NULL },
-	{ "aes128-sha256-modp3072-modpnone", "aes128-sha256", "aes128-sha256" },
-	{ "aes128-sha256", "aes128-sha256-modp3072-modpnone", "aes128-sha256" },
-	{ "aes128-sha256-modp3072-modpnone", "aes128-sha256-modpnone-modp3072", "aes128-sha256-modp3072" },
-	{ "aes128-sha256-modpnone-modp3072", "aes128-sha256-modp3072-modpnone", "aes128-sha256-modpnone" },
+	{ PROTO_ESP, "aes128", "aes128", "aes128" },
+	{ PROTO_ESP, "aes128", "aes256", NULL },
+	{ PROTO_ESP, "aes128-aes256", "aes256-aes128", "aes128" },
+	{ PROTO_ESP, "aes256-aes128", "aes128-aes256", "aes256" },
+	{ PROTO_ESP, "aes128-aes256-sha1-sha256", "aes256-aes128-sha256-sha1", "aes128-sha1" },
+	{ PROTO_ESP, "aes256-aes128-sha256-sha1", "aes128-aes256-sha1-sha256", "aes256-sha256" },
+	{ PROTO_ESP, "aes128-sha256-modp3072", "aes128-sha256", NULL },
+	{ PROTO_ESP, "aes128-sha256", "aes128-sha256-modp3072", NULL },
+	{ PROTO_ESP, "aes128-sha256-modp3072", "aes128-sha256-modpnone", NULL },
+	{ PROTO_ESP, "aes128-sha256-modpnone", "aes128-sha256-modp3072", NULL },
+	{ PROTO_ESP, "aes128-sha256-modp3072-modpnone", "aes128-sha256", "aes128-sha256" },
+	{ PROTO_ESP, "aes128-sha256", "aes128-sha256-modp3072-modpnone", "aes128-sha256" },
+	{ PROTO_ESP, "aes128-sha256-modp3072-modpnone", "aes128-sha256-modpnone-modp3072", "aes128-sha256-modp3072" },
+	{ PROTO_ESP, "aes128-sha256-modpnone-modp3072", "aes128-sha256-modp3072-modpnone", "aes128-sha256-modpnone" },
+	{ PROTO_IKE, "aes128-sha256-modp3072", "aes128-sha256-modp3072", "aes128-sha256-modp3072" },
+	{ PROTO_IKE, "aes128-sha256-modp3072", "aes128-sha256-modp3072-modpnone", "aes128-sha256-modp3072" },
+	{ PROTO_IKE, "aes128-sha256-modp3072-modpnone", "aes128-sha256-modp3072", "aes128-sha256-modp3072" },
 };
 
 START_TEST(test_select)
 {
 	proposal_t *self, *other, *selected, *expected;
 
-	self = proposal_create_from_string(PROTO_ESP,
+	self = proposal_create_from_string(select_data[_i].proto,
 									   select_data[_i].self);
-	other = proposal_create_from_string(PROTO_ESP,
+	other = proposal_create_from_string(select_data[_i].proto,
 										select_data[_i].other);
 	selected = self->select(self, other, FALSE);
 	if (select_data[_i].expected)
 	{
-		expected = proposal_create_from_string(PROTO_ESP,
+		expected = proposal_create_from_string(select_data[_i].proto,
 											   select_data[_i].expected);
 		ck_assert(selected);
 		ck_assert_msg(expected->equals(expected, selected), "proposal %P does "
@@ -73,6 +135,10 @@ Suite *proposal_suite_create()
 
 	s = suite_create("proposal");
 
+	tc = tcase_create("create_from_string");
+	tcase_add_loop_test(tc, test_create_from_string, 0, countof(create_data));
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("select");
 	tcase_add_loop_test(tc, test_select, 0, countof(select_data));
 	suite_add_tcase(s, tc);