diff --git a/configs/sandbox_flattree_defconfig b/configs/sandbox_flattree_defconfig
index 5b6b28a..e7657d4 100644
--- a/configs/sandbox_flattree_defconfig
+++ b/configs/sandbox_flattree_defconfig
@@ -59,6 +59,7 @@
 CONFIG_CMD_SNTP=y
 CONFIG_CMD_DNS=y
 CONFIG_CMD_LINK_LOCAL=y
+CONFIG_IPV6_ROUTER_DISCOVERY=y
 CONFIG_CMD_EFIDEBUG=y
 CONFIG_CMD_RTC=y
 CONFIG_CMD_TIME=y