diff --git a/meta-google/recipes-google/networking/gbmc-bridge/gbmc-br-gw-src.sh b/meta-google/recipes-google/networking/gbmc-bridge/gbmc-br-gw-src.sh
index dd153ab..693c728 100644
--- a/meta-google/recipes-google/networking/gbmc-bridge/gbmc-br-gw-src.sh
+++ b/meta-google/recipes-google/networking/gbmc-bridge/gbmc-br-gw-src.sh
@@ -97,7 +97,7 @@
     if (( ip_bytes[0] & 0xfe == 0xfc || ip_bytes[8] != 0xfd )); then
       return 0
     fi
-    if (( ip_bytes[9] != 0 )); then
+    if (( ip_bytes[9] & 0x0f != 0 )); then
       local -n gbmc_br_gw_src_ip=gbmc_br_gw_src_ip_stateful
     else
       local -n gbmc_br_gw_src_ip=gbmc_br_gw_src_ip_stateless