diff --git a/tests/gnrc_tcp_client/Makefile b/tests/gnrc_tcp_client/Makefile
index 4521cf4ebc..00ed0218e3 100644
--- a/tests/gnrc_tcp_client/Makefile
+++ b/tests/gnrc_tcp_client/Makefile
@@ -2,7 +2,10 @@ include ../Makefile.tests_common
 
 # If no BOARD is found in the environment, use this default:
 BOARD ?= native
-PORT ?= tap1
+
+ifeq (native,$(BOARD))
+  PORT ?= tap1
+endif
 
 TCP_TARGET_ADDR ?= fe80::affe%5
 TCP_TARGET_PORT ?= 80
diff --git a/tests/gnrc_tcp_server/Makefile b/tests/gnrc_tcp_server/Makefile
index 83dc0421c8..8f95273e37 100644
--- a/tests/gnrc_tcp_server/Makefile
+++ b/tests/gnrc_tcp_server/Makefile
@@ -2,7 +2,10 @@ include ../Makefile.tests_common
 
 # If no BOARD is found in the environment, use this default:
 BOARD ?= native
-PORT ?= tap0
+
+ifeq (native,$(BOARD))
+  PORT ?= tap0
+endif
 
 TCP_LOCAL_ADDR ?= fe80::affe
 TCP_LOCAL_PORT ?= 80