diff --git a/libnm-core/nm-setting.c b/libnm-core/nm-setting.c
index ede4635a38..f103b753fc 100644
--- a/libnm-core/nm-setting.c
+++ b/libnm-core/nm-setting.c
@@ -1173,6 +1173,8 @@ nm_setting_diff (NMSetting *a,
 	guint i;
 	NMSettingDiffResult a_result = NM_SETTING_DIFF_RESULT_IN_A;
 	NMSettingDiffResult b_result = NM_SETTING_DIFF_RESULT_IN_B;
+	NMSettingDiffResult a_result_default = NM_SETTING_DIFF_RESULT_IN_A_DEFAULT;
+	NMSettingDiffResult b_result_default = NM_SETTING_DIFF_RESULT_IN_B_DEFAULT;
 	gboolean results_created = FALSE;
 
 	g_return_val_if_fail (results != NULL, FALSE);
@@ -1182,6 +1184,12 @@ nm_setting_diff (NMSetting *a,
 		g_return_val_if_fail (G_OBJECT_TYPE (a) == G_OBJECT_TYPE (b), FALSE);
 	}
 
+	if ((flags & (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) ==
+	             (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) {
+		/* conflicting flags: default to WITH_DEFAULT (clearing NO_DEFAULT). */
+		flags &= ~NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT;
+	}
+
 	/* If the caller is calling this function in a pattern like this to get
 	 * complete diffs:
 	 *
@@ -1194,6 +1202,8 @@ nm_setting_diff (NMSetting *a,
 	if (invert_results) {
 		a_result = NM_SETTING_DIFF_RESULT_IN_B;
 		b_result = NM_SETTING_DIFF_RESULT_IN_A;
+		a_result_default = NM_SETTING_DIFF_RESULT_IN_B_DEFAULT;
+		b_result_default = NM_SETTING_DIFF_RESULT_IN_A_DEFAULT;
 	}
 
 	if (*results == NULL) {
@@ -1206,8 +1216,7 @@ nm_setting_diff (NMSetting *a,
 
 	for (i = 0; i < n_property_specs; i++) {
 		GParamSpec *prop_spec = property_specs[i];
-		NMSettingDiffResult r = NM_SETTING_DIFF_RESULT_UNKNOWN, tmp;
-		gboolean different = TRUE;
+		NMSettingDiffResult r = NM_SETTING_DIFF_RESULT_UNKNOWN;
 
 		/* Handle compare flags */
 		if (!should_compare_prop (a, prop_spec->name, flags, prop_spec->flags))
@@ -1216,28 +1225,58 @@ nm_setting_diff (NMSetting *a,
 			continue;
 
 		if (b) {
+			gboolean different;
+
 			different = !NM_SETTING_GET_CLASS (a)->compare_property (a, b, prop_spec, flags);
 			if (different) {
+				gboolean a_is_default, b_is_default;
 				GValue value = G_VALUE_INIT;
 
 				g_value_init (&value, prop_spec->value_type);
 				g_object_get_property (G_OBJECT (a), prop_spec->name, &value);
-				if (!g_param_value_defaults (prop_spec, &value))
-					r |= a_result;
+				a_is_default = g_param_value_defaults (prop_spec, &value);
 
 				g_value_reset (&value);
 				g_object_get_property (G_OBJECT (b), prop_spec->name, &value);
-				if (!g_param_value_defaults (prop_spec, &value))
-					r |= b_result;
+				b_is_default = g_param_value_defaults (prop_spec, &value);
 
 				g_value_unset (&value);
+				if ((flags & NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT) == 0) {
+					if (!a_is_default)
+						r |= a_result;
+					if (!b_is_default)
+						r |= b_result;
+				} else {
+					r |= a_result | b_result;
+					if (a_is_default)
+						r |= a_result_default;
+					if (b_is_default)
+						r |= b_result_default;
+				}
 			}
-		} else
+		} else if ((flags & (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) == 0)
 			r = a_result;  /* only in A */
+		else {
+			GValue value = G_VALUE_INIT;
 
-		if (different) {
-			tmp = GPOINTER_TO_UINT (g_hash_table_lookup (*results, prop_spec->name));
-			g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (tmp | r));
+			g_value_init (&value, prop_spec->value_type);
+			g_object_get_property (G_OBJECT (a), prop_spec->name, &value);
+			if (!g_param_value_defaults (prop_spec, &value))
+				r |= a_result;
+			else if (flags & NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT)
+				r |= a_result | a_result_default;
+
+			g_value_unset (&value);
+		}
+
+		if (r != NM_SETTING_DIFF_RESULT_UNKNOWN) {
+			void *p;
+
+			if (g_hash_table_lookup_extended (*results, prop_spec->name, NULL, &p)) {
+				if ((r & GPOINTER_TO_UINT (p)) != r)
+					g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (r | GPOINTER_TO_UINT (p)));
+			} else
+				g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (r));
 		}
 	}
 	g_free (property_specs);
diff --git a/libnm-core/nm-setting.h b/libnm-core/nm-setting.h
index bf8dd23362..8e179f2a4f 100644
--- a/libnm-core/nm-setting.h
+++ b/libnm-core/nm-setting.h
@@ -125,6 +125,20 @@ typedef enum { /*< flags >*/
  * @NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS: ignore secrets for which
  * the secret's flags indicate the secret should not be saved to persistent
  * storage (ie, the secret's flag includes @NM_SETTING_SECRET_FLAG_NOT_SAVED)
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT: if this flag is set,
+ * nm_setting_diff() and nm_connection_diff() will also include properties that
+ * are set to their default value. See also @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT.
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT: if this flag is set,
+ * nm_setting_diff() and nm_connection_diff() will not include properties that
+ * are set to their default value. This is the opposite of
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT. If both flags are set together,
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT wins. If both flags are unset,
+ * this means to exclude default properties if there is a setting to compare,
+ * but include all properties, if the setting 'b' is missing. This is the legacy
+ * behaviour of libnm-util, where nm_setting_diff() behaved differently depending
+ * on whether the setting 'b' was available. If @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT
+ * is set, nm_setting_diff() will also set the flags @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT
+ * and @NM_SETTING_DIFF_RESULT_IN_B_DEFAULT, if the values are default values.
  *
  * These flags modify the comparison behavior when comparing two settings or
  * two connections.
@@ -136,7 +150,9 @@ typedef enum {
 	NM_SETTING_COMPARE_FLAG_IGNORE_ID = 0x00000002,
 	NM_SETTING_COMPARE_FLAG_IGNORE_SECRETS = 0x00000004,
 	NM_SETTING_COMPARE_FLAG_IGNORE_AGENT_OWNED_SECRETS = 0x00000008,
-	NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS = 0x00000010
+	NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS = 0x00000010,
+	NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT = 0x00000020,
+	NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT = 0x00000040,
 
 	/* 0x80000000 is used for a private flag */
 } NMSettingCompareFlags;
@@ -247,6 +263,10 @@ gboolean    nm_setting_compare       (NMSetting *a,
  * @NM_SETTING_DIFF_RESULT_UNKNOWN: unknown result
  * @NM_SETTING_DIFF_RESULT_IN_A: the property is present in setting A
  * @NM_SETTING_DIFF_RESULT_IN_B: the property is present in setting B
+ * @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT: the property is present in
+ * setting A but is set to the default value. This flag is only set,
+ * if you specify @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT.
+ * @NM_SETTING_DIFF_RESULT_IN_B_DEFAULT: analog to @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT.
  *
  * These values indicate the result of a setting difference operation.
  **/
@@ -254,6 +274,8 @@ typedef enum {
 	NM_SETTING_DIFF_RESULT_UNKNOWN = 0x00000000,
 	NM_SETTING_DIFF_RESULT_IN_A =    0x00000001,
 	NM_SETTING_DIFF_RESULT_IN_B =    0x00000002,
+	NM_SETTING_DIFF_RESULT_IN_A_DEFAULT = 0x00000004,
+	NM_SETTING_DIFF_RESULT_IN_B_DEFAULT = 0x00000004,
 } NMSettingDiffResult;
 
 gboolean    nm_setting_diff          (NMSetting *a,
diff --git a/libnm-util/nm-setting.c b/libnm-util/nm-setting.c
index 0ca28dba16..160858d933 100644
--- a/libnm-util/nm-setting.c
+++ b/libnm-util/nm-setting.c
@@ -713,6 +713,8 @@ nm_setting_diff (NMSetting *a,
 	guint i;
 	NMSettingDiffResult a_result = NM_SETTING_DIFF_RESULT_IN_A;
 	NMSettingDiffResult b_result = NM_SETTING_DIFF_RESULT_IN_B;
+	NMSettingDiffResult a_result_default = NM_SETTING_DIFF_RESULT_IN_A_DEFAULT;
+	NMSettingDiffResult b_result_default = NM_SETTING_DIFF_RESULT_IN_B_DEFAULT;
 	gboolean results_created = FALSE;
 
 	g_return_val_if_fail (results != NULL, FALSE);
@@ -722,6 +724,12 @@ nm_setting_diff (NMSetting *a,
 		g_return_val_if_fail (G_OBJECT_TYPE (a) == G_OBJECT_TYPE (b), FALSE);
 	}
 
+	if ((flags & (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) ==
+	             (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) {
+		/* conflicting flags: default to WITH_DEFAULT (clearing NO_DEFAULT). */
+		flags &= ~NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT;
+	}
+
 	/* If the caller is calling this function in a pattern like this to get
 	 * complete diffs:
 	 *
@@ -734,6 +742,8 @@ nm_setting_diff (NMSetting *a,
 	if (invert_results) {
 		a_result = NM_SETTING_DIFF_RESULT_IN_B;
 		b_result = NM_SETTING_DIFF_RESULT_IN_A;
+		a_result_default = NM_SETTING_DIFF_RESULT_IN_B_DEFAULT;
+		b_result_default = NM_SETTING_DIFF_RESULT_IN_A_DEFAULT;
 	}
 
 	if (*results == NULL) {
@@ -746,8 +756,7 @@ nm_setting_diff (NMSetting *a,
 
 	for (i = 0; i < n_property_specs; i++) {
 		GParamSpec *prop_spec = property_specs[i];
-		NMSettingDiffResult r = NM_SETTING_DIFF_RESULT_UNKNOWN, tmp;
-		gboolean different = TRUE;
+		NMSettingDiffResult r = NM_SETTING_DIFF_RESULT_UNKNOWN;
 
 		/* Handle compare flags */
 		if (!should_compare_prop (a, prop_spec->name, flags, prop_spec->flags))
@@ -756,28 +765,58 @@ nm_setting_diff (NMSetting *a,
 			continue;
 
 		if (b) {
+			gboolean different;
+
 			different = !NM_SETTING_GET_CLASS (a)->compare_property (a, b, prop_spec, flags);
 			if (different) {
+				gboolean a_is_default, b_is_default;
 				GValue value = G_VALUE_INIT;
 
 				g_value_init (&value, prop_spec->value_type);
 				g_object_get_property (G_OBJECT (a), prop_spec->name, &value);
-				if (!g_param_value_defaults (prop_spec, &value))
-					r |= a_result;
+				a_is_default = g_param_value_defaults (prop_spec, &value);
 
 				g_value_reset (&value);
 				g_object_get_property (G_OBJECT (b), prop_spec->name, &value);
-				if (!g_param_value_defaults (prop_spec, &value))
-					r |= b_result;
+				b_is_default = g_param_value_defaults (prop_spec, &value);
 
 				g_value_unset (&value);
+				if ((flags & NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT) == 0) {
+					if (!a_is_default)
+						r |= a_result;
+					if (!b_is_default)
+						r |= b_result;
+				} else {
+					r |= a_result | b_result;
+					if (a_is_default)
+						r |= a_result_default;
+					if (b_is_default)
+						r |= b_result_default;
+				}
 			}
-		} else
+		} else if ((flags & (NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT | NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT)) == 0)
 			r = a_result;  /* only in A */
+		else {
+			GValue value = G_VALUE_INIT;
 
-		if (different) {
-			tmp = GPOINTER_TO_UINT (g_hash_table_lookup (*results, prop_spec->name));
-			g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (tmp | r));
+			g_value_init (&value, prop_spec->value_type);
+			g_object_get_property (G_OBJECT (a), prop_spec->name, &value);
+			if (!g_param_value_defaults (prop_spec, &value))
+				r |= a_result;
+			else if (flags & NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT)
+				r |= a_result | a_result_default;
+
+			g_value_unset (&value);
+		}
+
+		if (r != NM_SETTING_DIFF_RESULT_UNKNOWN) {
+			void *p;
+
+			if (g_hash_table_lookup_extended (*results, prop_spec->name, NULL, &p)) {
+				if ((r & GPOINTER_TO_UINT (p)) != r)
+					g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (r | GPOINTER_TO_UINT (p)));
+			} else
+				g_hash_table_insert (*results, g_strdup (prop_spec->name), GUINT_TO_POINTER (r));
 		}
 	}
 	g_free (property_specs);
diff --git a/libnm-util/nm-setting.h b/libnm-util/nm-setting.h
index b58137a6e7..28c6975a8d 100644
--- a/libnm-util/nm-setting.h
+++ b/libnm-util/nm-setting.h
@@ -124,6 +124,20 @@ typedef enum {
  * @NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS: ignore secrets for which
  * the secret's flags indicate the secret should not be saved to persistent
  * storage (ie, the secret's flag includes @NM_SETTING_SECRET_FLAG_NOT_SAVED)
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT: if this flag is set,
+ * nm_setting_diff() and nm_connection_diff() will also include properties that
+ * are set to their default value. See also @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT.
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT: if this flag is set,
+ * nm_setting_diff() and nm_connection_diff() will not include properties that
+ * are set to their default value. This is the opposite of
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT. If both flags are set together,
+ * @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT wins. If both flags are unset,
+ * this means to exclude default properties if there is a setting to compare,
+ * but include all properties, if the setting 'b' is missing. This is the legacy
+ * behaviour of libnm-util, where nm_setting_diff() behaved differently depending
+ * on whether the setting 'b' was available. If @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT
+ * is set, nm_setting_diff() will also set the flags @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT
+ * and @NM_SETTING_DIFF_RESULT_IN_B_DEFAULT, if the values are default values.
  *
  * These flags modify the comparison behavior when comparing two settings or
  * two connections.
@@ -135,7 +149,9 @@ typedef enum {
 	NM_SETTING_COMPARE_FLAG_IGNORE_ID = 0x00000002,
 	NM_SETTING_COMPARE_FLAG_IGNORE_SECRETS = 0x00000004,
 	NM_SETTING_COMPARE_FLAG_IGNORE_AGENT_OWNED_SECRETS = 0x00000008,
-	NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS = 0x00000010
+	NM_SETTING_COMPARE_FLAG_IGNORE_NOT_SAVED_SECRETS = 0x00000010,
+	NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT = 0x00000020,
+	NM_SETTING_COMPARE_FLAG_DIFF_RESULT_NO_DEFAULT = 0x00000040,
 
 	/* 0x80000000 is used for a private flag */
 } NMSettingCompareFlags;
@@ -267,6 +283,10 @@ gboolean    nm_setting_compare       (NMSetting *a,
  * @NM_SETTING_DIFF_RESULT_UNKNOWN: unknown result
  * @NM_SETTING_DIFF_RESULT_IN_A: the property is present in setting A
  * @NM_SETTING_DIFF_RESULT_IN_B: the property is present in setting B
+ * @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT: the property is present in
+ * setting A but is set to the default value. This flag is only set,
+ * if you specify @NM_SETTING_COMPARE_FLAG_DIFF_RESULT_WITH_DEFAULT.
+ * @NM_SETTING_DIFF_RESULT_IN_B_DEFAULT: analog to @NM_SETTING_DIFF_RESULT_IN_A_DEFAULT.
  *
  * These values indicate the result of a setting difference operation.
  **/
@@ -274,6 +294,8 @@ typedef enum {
 	NM_SETTING_DIFF_RESULT_UNKNOWN = 0x00000000,
 	NM_SETTING_DIFF_RESULT_IN_A =    0x00000001,
 	NM_SETTING_DIFF_RESULT_IN_B =    0x00000002,
+	NM_SETTING_DIFF_RESULT_IN_A_DEFAULT = 0x00000004,
+	NM_SETTING_DIFF_RESULT_IN_B_DEFAULT = 0x00000004,
 } NMSettingDiffResult;
 
 gboolean    nm_setting_diff          (NMSetting *a,