diff --git a/devstack/settings b/devstack/settings
index 9783efdd65..cafa85384a 100644
--- a/devstack/settings
+++ b/devstack/settings
@@ -9,4 +9,8 @@ source $DEST/ironic/devstack/common_settings
 local_mtu=$(ip link show | sed -ne 's/.*mtu \([0-9]\+\).*/\1/p' | sort -n | head -1)
 # 50 bytes is overhead for vxlan (which is greater than GRE
 # allowing us to use either overlay option with this MTU.
-PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 50))}
+# However, if traffic is flowing over IPv6 tunnels, then
+# The overhead is essentially another 100 bytes. In order to
+# handle both cases, lets go ahead and drop the maximum by
+# 100 bytes.
+PUBLIC_BRIDGE_MTU=${OVERRIDE_PUBLIC_BRIDGE_MTU:-$((local_mtu - 100))}
diff --git a/zuul.d/ironic-jobs.yaml b/zuul.d/ironic-jobs.yaml
index 32cf9e649a..ae1887c9db 100644
--- a/zuul.d/ironic-jobs.yaml
+++ b/zuul.d/ironic-jobs.yaml
@@ -30,7 +30,6 @@
         DEFAULT_INSTANCE_TYPE: baremetal
         FORCE_CONFIG_DRIVE: True
         INSTALL_TEMPEST: False # Don't install a tempest package globaly
-        OVERRIDE_PUBLIC_BRIDGE_MTU: 1350
         TEMPEST_PLUGINS: "{{ ansible_user_dir }}/src/opendev.org/openstack/ironic-tempest-plugin"
         VIRT_DRIVER: ironic
         BUILD_TIMEOUT: 720
@@ -389,7 +388,6 @@
         IRONIC_VM_LOG_DIR: '{{ devstack_base_dir }}/ironic-bm-logs'
         IRONIC_VM_SPECS_RAM: 384
         IRONIC_VM_SPECS_DISK: 4
-        OVERRIDE_PUBLIC_BRIDGE_MTU: 1350
         OVS_BRIDGE_MAPPINGS: 'mynetwork:brbm,public:br-infra'
         OVS_PHYSICAL_BRIDGE: brbm
         PHYSICAL_NETWORK: mynetwork