diff --git a/coreapi/linphonecore.c b/coreapi/linphonecore.c
index bb44d5da3..f78a5d5cd 100644
--- a/coreapi/linphonecore.c
+++ b/coreapi/linphonecore.c
@@ -5155,12 +5155,17 @@ const char *linphone_core_get_nat_address_resolved(LinphoneCore *lc)
 
 void linphone_core_set_firewall_policy(LinphoneCore *lc, LinphoneFirewallPolicy pol) {
 	LinphoneNatPolicy *nat_policy;
+	char *stun_server = NULL;
+	char *stun_server_username = NULL;
 	
 	if (lc->nat_policy != NULL) {
 		nat_policy = linphone_nat_policy_ref(lc->nat_policy);
+		stun_server = ms_strdup(linphone_nat_policy_get_stun_server(lc->nat_policy));
+		stun_server_username = ms_strdup(linphone_nat_policy_get_stun_server_username(lc->nat_policy));
 		linphone_nat_policy_clear(nat_policy);
 	} else {
 		nat_policy = linphone_core_create_nat_policy(lc);
+		stun_server = ms_strdup(linphone_core_get_stun_server(lc));
 	}
 
 	switch (pol) {
@@ -5184,7 +5189,14 @@ void linphone_core_set_firewall_policy(LinphoneCore *lc, LinphoneFirewallPolicy
 			break;
 	}
 
-	linphone_nat_policy_set_stun_server(nat_policy, linphone_core_get_stun_server(lc));
+	if (stun_server_username != NULL) {
+		linphone_nat_policy_set_stun_server_username(nat_policy, stun_server_username);
+		ms_free(stun_server_username);
+	}
+	if (stun_server != NULL) {
+		linphone_nat_policy_set_stun_server(nat_policy, stun_server);
+		ms_free(stun_server);
+	}
 	linphone_core_set_nat_policy(lc, nat_policy);
 	linphone_nat_policy_unref(nat_policy);
 }
diff --git a/coreapi/misc.c b/coreapi/misc.c
index 9e63a94e6..5cc467d67 100644
--- a/coreapi/misc.c
+++ b/coreapi/misc.c
@@ -637,18 +637,31 @@ void linphone_core_enable_forced_ice_relay(LinphoneCore *lc, bool_t enable) {
 
 static void stun_auth_requested_cb(LinphoneCall *call, const char *realm, const char *nonce, const char **username, const char **password, const char **ha1) {
 	LinphoneProxyConfig *proxy = NULL;
+	const LinphoneNatPolicy *nat_policy = NULL;
 	const LinphoneAddress *addr = NULL;
 	const LinphoneAuthInfo *auth_info = NULL;
 	LinphoneCore *lc = call->core;
 	const char *user;
 
-	// Get the username from the proxy config
+	// Get the username from the nat policy or the proxy config
 	if (call->dest_proxy != NULL) proxy = call->dest_proxy;
 	else proxy = linphone_core_get_default_proxy_config(call->core);
 	if (proxy == NULL) return;
-	addr = linphone_proxy_config_get_identity_address(proxy);
-	if (addr == NULL) return;
-	user = linphone_address_get_username(addr);
+	nat_policy = linphone_proxy_config_get_nat_policy(proxy);
+	if (nat_policy != NULL) {
+		user = linphone_nat_policy_get_stun_server_username(nat_policy);
+	} else {
+		nat_policy = linphone_core_get_nat_policy(call->core);
+		if (nat_policy != NULL) {
+			user = linphone_nat_policy_get_stun_server_username(nat_policy);
+		}
+	}
+	if (user == NULL) {
+		/* If the username has not been found in the nat_policy, take the username from the currently used proxy config. */
+		addr = linphone_proxy_config_get_identity_address(proxy);
+		if (addr == NULL) return;
+		user = linphone_address_get_username(addr);
+	}
 	if (user == NULL) return;
 
 	auth_info = linphone_core_find_auth_info(lc, realm, user, NULL);
diff --git a/coreapi/nat_policy.c b/coreapi/nat_policy.c
index f28bf7985..9d172a0a0 100644
--- a/coreapi/nat_policy.c
+++ b/coreapi/nat_policy.c
@@ -38,6 +38,7 @@ static LinphoneNatPolicy * linphone_nat_policy_new(LinphoneCore *lc) {
 static void linphone_nat_policy_destroy(LinphoneNatPolicy *policy) {
 	if (policy->ref) belle_sip_free(policy->ref);
 	if (policy->stun_server) belle_sip_free(policy->stun_server);
+	if (policy->stun_server_username) belle_sip_free(policy->stun_server_username);
 	if (policy->stun_addrinfo) freeaddrinfo(policy->stun_addrinfo);
 }
 
@@ -66,6 +67,7 @@ static void _linphone_nat_policy_save_to_config(const LinphoneNatPolicy *policy,
 	section = belle_sip_strdup_printf("nat_policy_%i", index);
 	lp_config_set_string(config, section, "ref", policy->ref);
 	lp_config_set_string(config, section, "stun_server", policy->stun_server);
+	lp_config_set_string(config, section, "stun_server_username", policy->stun_server_username);
 	if (linphone_nat_policy_upnp_enabled(policy)) {
 		l = ms_list_append(l, "upnp");
 	} else {
@@ -183,6 +185,21 @@ void linphone_nat_policy_set_stun_server(LinphoneNatPolicy *policy, const char *
 	}
 }
 
+const char * linphone_nat_policy_get_stun_server_username(const LinphoneNatPolicy *policy) {
+	return policy->stun_server_username;
+}
+
+void linphone_nat_policy_set_stun_server_username(LinphoneNatPolicy *policy, const char *username) {
+	char *new_username = NULL;
+
+	if (username != NULL) new_username = belle_sip_strdup(username);
+	if (policy->stun_server_username != NULL) {
+		belle_sip_free(policy->stun_server_username);
+		policy->stun_server_username = NULL;
+	}
+	if (new_username != NULL) policy->stun_server_username = new_username;
+}
+
 static void stun_server_resolved(LinphoneNatPolicy *policy, const char *name, struct addrinfo *addrinfo) {
 	if (policy->stun_addrinfo) {
 		belle_sip_freeaddrinfo(policy->stun_addrinfo);
@@ -259,9 +276,11 @@ LinphoneNatPolicy * linphone_core_create_nat_policy_from_config(LinphoneCore *lc
 			const char *config_ref = lp_config_get_string(config, section, "ref", NULL);
 			if ((config_ref != NULL) && (strcmp(config_ref, ref) == 0)) {
 				const char *server = lp_config_get_string(config, section, "stun_server", NULL);
+				const char *username = lp_config_get_string(config, section, "stun_server_username", NULL);
 				MSList *l = lp_config_get_string_list(config, section, "protocols", NULL);
 				policy = _linphone_nat_policy_new_with_ref(lc, ref);
 				if (server != NULL) linphone_nat_policy_set_stun_server(policy, server);
+				if (username != NULL) linphone_nat_policy_set_stun_server_username(policy, username);
 				if (l != NULL) {
 					bool_t upnp_enabled = FALSE;
 					MSList *elem;
diff --git a/coreapi/nat_policy.h b/coreapi/nat_policy.h
index 96147ce67..e122508aa 100644
--- a/coreapi/nat_policy.h
+++ b/coreapi/nat_policy.h
@@ -131,7 +131,7 @@ LINPHONE_PUBLIC bool_t linphone_nat_policy_upnp_enabled(const LinphoneNatPolicy
 LINPHONE_PUBLIC void linphone_nat_policy_enable_upnp(LinphoneNatPolicy *policy, bool_t enable);
 
 /**
- * Get the STUN server to use with this NAT policy.
+ * Get the STUN/TURN server to use with this NAT policy.
  * Used when STUN or TURN are enabled.
  * @param[in] policy LinphoneNatPolicy object
  * @return The STUN server used by this NAT policy.
@@ -139,13 +139,31 @@ LINPHONE_PUBLIC void linphone_nat_policy_enable_upnp(LinphoneNatPolicy *policy,
 LINPHONE_PUBLIC const char * linphone_nat_policy_get_stun_server(const LinphoneNatPolicy *policy);
 
 /**
- * Set the STUN server to use with this NAT policy.
+ * Set the STUN/TURN server to use with this NAT policy.
  * Used when STUN or TURN are enabled.
  * @param[in] policy LinphoneNatPolicy object
  * @param[in] stun_server The STUN server to use with this NAT policy.
  */
 LINPHONE_PUBLIC void linphone_nat_policy_set_stun_server(LinphoneNatPolicy *policy, const char *stun_server);
 
+/**
+ * Get the username used to authenticate with the STUN/TURN server.
+ * The authentication will search for a LinphoneAuthInfo with this username.
+ * If it is not set the username of the currently used LinphoneProxyConfig is used to search for a LinphoneAuthInfo.
+ * @param[in] policy LinphoneNatPolicy object
+ * @return The username used to authenticate with the STUN/TURN server.
+ */
+LINPHONE_PUBLIC const char * linphone_nat_policy_get_stun_server_username(const LinphoneNatPolicy *policy);
+
+/**
+ * Seth the username used to authenticate with the STUN/TURN server.
+ * The authentication will search for a LinphoneAuthInfo with this username.
+ * If it is not set the username of the currently used LinphoneProxyConfig is used to search for a LinphoneAuthInfo.
+ * @param[in] policy LinphoneNatPolicy object
+ * @param[in] username The username used to authenticate with the STUN/TURN server.
+ */
+LINPHONE_PUBLIC void linphone_nat_policy_set_stun_server_username(LinphoneNatPolicy *policy, const char *username);
+
 /**
  * Start a STUN server DNS resolution.
  * @param[in] policy LinphoneNatPolicy object
diff --git a/coreapi/private.h b/coreapi/private.h
index 6d36cf6ed..365e0c9e4 100644
--- a/coreapi/private.h
+++ b/coreapi/private.h
@@ -1194,6 +1194,7 @@ struct _LinphoneNatPolicy {
 	SalResolverContext *stun_resolver_context;
 	struct addrinfo *stun_addrinfo;
 	char *stun_server;
+	char *stun_server_username;
 	char *ref;
 	bool_t stun_enabled;
 	bool_t turn_enabled;