diff --git a/coreapi/proxy.c b/coreapi/proxy.c
index 80eb5d522..babd13e34 100644
--- a/coreapi/proxy.c
+++ b/coreapi/proxy.c
@@ -244,7 +244,13 @@ static char *guess_contact_for_register(LinphoneProxyConfig *obj){
 		contact=linphone_address_new(obj->reg_identity);
 		linphone_address_set_domain (contact,localip);
 		linphone_address_set_port_int(contact,linphone_core_get_sip_port(obj->lc));
-		ret=linphone_address_as_string_uri_only (contact);
+		linphone_address_set_display_name(contact,NULL);
+		LCSipTransports tr;
+		linphone_core_get_sip_transports(obj->lc,&tr);
+		if (tr.udp_port <= 0 && tr.tcp_port>0) {
+			sal_address_add_param(contact,"transport","tcp");
+		}
+		ret=linphone_address_as_string(contact);
 		linphone_address_destroy(contact);
 	}
 	linphone_address_destroy (proxy);
diff --git a/coreapi/sal.h b/coreapi/sal.h
index 9790b8c71..e6c1292a2 100644
--- a/coreapi/sal.h
+++ b/coreapi/sal.h
@@ -57,7 +57,7 @@ void sal_address_clean(SalAddress *addr);
 char *sal_address_as_string(const SalAddress *u);
 char *sal_address_as_string_uri_only(const SalAddress *u);
 void sal_address_destroy(SalAddress *u);
-
+void sal_address_add_param(SalAddress *u,const char* name,const char* value);
 
 
 
diff --git a/coreapi/sal_eXosip2.c b/coreapi/sal_eXosip2.c
index fa6fb5f11..df770ce12 100644
--- a/coreapi/sal_eXosip2.c
+++ b/coreapi/sal_eXosip2.c
@@ -1749,6 +1749,9 @@ char *sal_address_as_string_uri_only(const SalAddress *u){
 	osip_free(tmp);
 	return ret;
 }
+void sal_address_add_param(SalAddress *u,const char* name,const char* value) {
+	osip_uri_uparam_add	(((osip_from_t*)u)->url,ms_strdup(name),ms_strdup(value));
+}
 
 void sal_address_destroy(SalAddress *u){
 	osip_from_free((osip_from_t*)u);