The default TCP TIME_WAIT timeout for Cloud NAT is scheduled to decrease from 120 seconds to 30 seconds, across all...

The default TCP TIME_WAIT timeout for Cloud NAT is scheduled to decrease from 120 seconds to 30 seconds, across all regions, as follows:

• From June 30 to September 29, 2026: new Cloud NAT gateways will use either the 120-second or 30-second default, depending on when the update is deployed in a specific region. • On or after September 30, 2026: all new Cloud NAT gateways in all regions will use the 30-second default.

Impact on gateways

• New gateways: after the update is deployed in a region, all new Cloud NAT gateways created in that region will use the 30-second default. This change also applies if a pre-update gateway is deleted and then recreated. • Existing gateways: Cloud NAT gateways created before the regional update will retain the 120-second default. You can adjust this value by using the --tcp-time-wait-timeout flag at any time. Cloud NAT gateways configured with a custom TIME_WAIT value aren't affected and will continue to use your configured custom value.

The following table outlines the applicable default timeout for new gateways throughout the deployment timeline.