diff --git a/src/backend.c b/src/backend.c
index 6ec85ae1f..0a7875cdf 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -2669,11 +2669,15 @@ int backend_parse_balance(const char **args, char **err, struct proxy *curproxy)
 static int
 smp_fetch_nbsrv(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
-	struct proxy *px;
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
 
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	px = args->data.prx;
 
 	smp->data.u.sint = be_usable_srv(px);
 
@@ -2708,12 +2712,18 @@ static int
 smp_fetch_connslots(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
 	struct server *iterator;
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
 
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
 	smp->data.u.sint = 0;
 
-	for (iterator = args->data.prx->srv; iterator; iterator = iterator->next) {
+	for (iterator = px->srv; iterator; iterator = iterator->next) {
 		if (iterator->cur_state == SRV_ST_STOPPED)
 			continue;
 
@@ -2822,9 +2832,16 @@ smp_fetch_srv_name(const struct arg *args, struct sample *smp, const char *kw, v
 static int
 smp_fetch_be_sess_rate(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = read_freq_ctr(&args->data.prx->be_sess_per_sec);
+	smp->data.u.sint = read_freq_ctr(&px->be_sess_per_sec);
 	return 1;
 }
 
@@ -2835,9 +2852,16 @@ smp_fetch_be_sess_rate(const struct arg *args, struct sample *smp, const char *k
 static int
 smp_fetch_be_conn(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = args->data.prx->beconn;
+	smp->data.u.sint = px->beconn;
 	return 1;
 }
 
@@ -2850,14 +2874,19 @@ static int
 smp_fetch_be_conn_free(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
 	struct server *iterator;
-	struct proxy *px;
+	struct proxy *px = args->data.prx;
 	unsigned int maxconn;
 
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
 	smp->data.u.sint = 0;
 
-	for (iterator = args->data.prx->srv; iterator; iterator = iterator->next) {
+	for (iterator = px->srv; iterator; iterator = iterator->next) {
 		if (iterator->cur_state == SRV_ST_STOPPED)
 			continue;
 
@@ -2888,9 +2917,16 @@ smp_fetch_be_conn_free(const struct arg *args, struct sample *smp, const char *k
 static int
 smp_fetch_queue_size(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = args->data.prx->totpend;
+	smp->data.u.sint = px->totpend;
 	return 1;
 }
 
@@ -2905,12 +2941,16 @@ smp_fetch_queue_size(const struct arg *args, struct sample *smp, const char *kw,
 static int
 smp_fetch_avg_queue_size(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
 	int nbsrv;
-	struct proxy *px;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
 
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	px = args->data.prx;
 
 	nbsrv = be_usable_srv(px);
 
diff --git a/src/frontend.c b/src/frontend.c
index 6aa102701..f976cc831 100644
--- a/src/frontend.c
+++ b/src/frontend.c
@@ -211,9 +211,16 @@ smp_fetch_fe_defbe(const struct arg *args, struct sample *smp, const char *kw, v
 static int
 smp_fetch_fe_req_rate(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = read_freq_ctr(&args->data.prx->fe_req_per_sec);
+	smp->data.u.sint = read_freq_ctr(&px->fe_req_per_sec);
 	return 1;
 }
 
@@ -224,9 +231,16 @@ smp_fetch_fe_req_rate(const struct arg *args, struct sample *smp, const char *kw
 static int
 smp_fetch_fe_sess_rate(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = read_freq_ctr(&args->data.prx->fe_sess_per_sec);
+	smp->data.u.sint = read_freq_ctr(&px->fe_sess_per_sec);
 	return 1;
 }
 
@@ -237,9 +251,16 @@ smp_fetch_fe_sess_rate(const struct arg *args, struct sample *smp, const char *k
 static int
 smp_fetch_fe_conn(const struct arg *args, struct sample *smp, const char *kw, void *private)
 {
+	struct proxy *px = args->data.prx;
+
+	if (px == NULL)
+		return 0;
+	if (px->cap & PR_CAP_DEF)
+		px = smp->px;
+
 	smp->flags = SMP_F_VOL_TEST;
 	smp->data.type = SMP_T_SINT;
-	smp->data.u.sint = args->data.prx->feconn;
+	smp->data.u.sint = px->feconn;
 	return 1;
 }
 
diff --git a/src/sample.c b/src/sample.c
index d5ce8ad6c..9200ca303 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -1217,8 +1217,16 @@ int smp_resolve_args(struct proxy *p, char **err)
 					break;
 				}
 			}
-			else
+			else {
+				if (px->cap & PR_CAP_DEF) {
+					memprintf(err, "%sparsing [%s:%d]: backend name must be set in arg %d of %s%s%s%s '%s' %s proxy '%s'.\n",
+						  *err ? *err : "", cur->file, cur->line,
+						  cur->arg_pos + 1, conv_pre, conv_ctx, conv_pos, ctx, cur->kw, where, p->id);
+					cfgerr++;
+					break;
+				}
 				sname = arg->data.str.area;
+			}
 
 			srv = findserver(px, sname);
 			if (!srv) {
@@ -1293,8 +1301,16 @@ int smp_resolve_args(struct proxy *p, char **err)
 		case ARGT_TAB:
 			if (arg->data.str.data)
 				stktname = arg->data.str.area;
-			else
+			else {
+				if (px->cap & PR_CAP_DEF) {
+					memprintf(err, "%sparsing [%s:%d]: table name must be set in arg %d of %s%s%s%s '%s' %s proxy '%s'.\n",
+						  *err ? *err : "", cur->file, cur->line,
+						  cur->arg_pos + 1, conv_pre, conv_ctx, conv_pos, ctx, cur->kw, where, p->id);
+					cfgerr++;
+					break;
+				}
 				stktname = px->id;
+			}
 
 			t = stktable_find_by_name(stktname);
 			if (!t) {