diff --git a/neutron/agent/common/config.py b/neutron/agent/common/config.py
index d3594c4b81b..8c48b25b56d 100644
--- a/neutron/agent/common/config.py
+++ b/neutron/agent/common/config.py
@@ -84,7 +84,6 @@ AVAILABILITY_ZONE_OPTS = [
 
 EXT_NET_BRIDGE_OPTS = [
     cfg.StrOpt('external_network_bridge', default='br-ex',
-               deprecated_for_removal=True,
                help=_("Name of bridge used for external network "
                       "traffic. This should be set to an empty value for the "
                       "Linux Bridge. When this parameter is set, each L3 "
diff --git a/neutron/agent/l3/agent.py b/neutron/agent/l3/agent.py
index ddcb50da5f1..7735d4e9a01 100644
--- a/neutron/agent/l3/agent.py
+++ b/neutron/agent/l3/agent.py
@@ -263,6 +263,12 @@ class L3NATAgent(firewall_l3_agent.FWaaSL3AgentRpcCallback,
             msg = _LE('An interface driver must be specified')
             LOG.error(msg)
             raise SystemExit(1)
+        if self.conf.external_network_bridge:
+            LOG.warning(_LW("Using an 'external_network_bridge' value other "
+                            "than '' is deprecated. Any other values may "
+                            "not be supported in the future. Note that the "
+                            "default value is 'br-ex' so it must be "
+                            "explicitly set to a blank value."))
 
         if self.conf.ipv6_gateway:
             # ipv6_gateway configured. Check for valid v6 link-local address.