diff --git a/tests/gnrc_ipv6_ext/Makefile b/tests/gnrc_ipv6_ext/Makefile
index 6ad7974e6ef0924ba5fbd731b1d3fa7da29fce0e..36253d2bebf934ee8b01460ea7c6040c22a33e62 100644
--- a/tests/gnrc_ipv6_ext/Makefile
+++ b/tests/gnrc_ipv6_ext/Makefile
@@ -22,6 +22,8 @@ USEMODULE += gnrc_udp
 # Add also the shell, some shell commands
 USEMODULE += ps
 
+CFLAGS += -DGNRC_NETIF_IPV6_ADDRS_NUMOF=3
+
 include $(RIOTBASE)/Makefile.include
 
 # The test can check more things with ENABLE_DEBUG set to 1 in gnrc_ipv6.c