diff --git a/modules/net-ilb/README.md b/modules/net-ilb/README.md
index 5573e525..00a17d1d 100644
--- a/modules/net-ilb/README.md
+++ b/modules/net-ilb/README.md
@@ -179,7 +179,7 @@ module "ilb" {
 | [region](variables.tf#L206) | GCP region. | <code>string</code> | ✓ |  |
 | [vpc_config](variables.tf#L217) | VPC-level configuration. | <code title="object&#40;&#123;&#10;  network    &#61; string&#10;  subnetwork &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> | ✓ |  |
 | [address](variables.tf#L17) | Optional IP address used for the forwarding rule. | <code>string</code> |  | <code>null</code> |
-| [backend_service_config](variables.tf#L23) | Backend service level configuration. | <code title="object&#40;&#123;&#10;  connection_draining_timeout_sec &#61; optional&#40;number&#41;&#10;  connection_tracking &#61; optional&#40;object&#40;&#123;&#10;    idle_timeout_sec          &#61; optional&#40;number&#41;&#10;    persist_conn_on_unhealthy &#61; optional&#40;string&#41;&#10;    tracking_mode             &#61; optional&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;  enable_subsetting &#61; optional&#40;bool&#41;&#10;  failover_config &#61; optional&#40;object&#40;&#123;&#10;    disable_conn_drain        &#61; optional&#40;bool&#41;&#10;    drop_traffic_if_unhealthy &#61; optional&#40;bool&#41;&#10;    ratio                     &#61; optional&#40;number&#41;&#10;  &#125;&#41;&#41;&#10;  log_sample_rate  &#61; optional&#40;number&#41;&#10;  session_affinity &#61; optional&#40;string&#41;&#10;  timeout_sec      &#61; optional&#40;number&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>&#123;&#125;</code> |
+| [backend_service_config](variables.tf#L23) | Backend service level configuration. | <code title="object&#40;&#123;&#10;  connection_draining_timeout_sec &#61; optional&#40;number&#41;&#10;  connection_tracking &#61; optional&#40;object&#40;&#123;&#10;    idle_timeout_sec          &#61; optional&#40;number&#41;&#10;    persist_conn_on_unhealthy &#61; optional&#40;string&#41;&#10;    track_per_session         &#61; optional&#40;true&#41;&#10;  &#125;&#41;&#41;&#10;  enable_subsetting &#61; optional&#40;bool&#41;&#10;  failover_config &#61; optional&#40;object&#40;&#123;&#10;    disable_conn_drain        &#61; optional&#40;bool&#41;&#10;    drop_traffic_if_unhealthy &#61; optional&#40;bool&#41;&#10;    ratio                     &#61; optional&#40;number&#41;&#10;  &#125;&#41;&#41;&#10;  log_sample_rate  &#61; optional&#40;number&#41;&#10;  session_affinity &#61; optional&#40;string&#41;&#10;  timeout_sec      &#61; optional&#40;number&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>&#123;&#125;</code> |
 | [backends](variables.tf#L56) | Load balancer backends, balancing mode is one of 'CONNECTION' or 'UTILIZATION'. | <code title="list&#40;object&#40;&#123;&#10;  group          &#61; string&#10;  balancing_mode &#61; optional&#40;string, &#34;CONNECTION&#34;&#41;&#10;  description    &#61; optional&#40;string, &#34;Terraform managed.&#34;&#41;&#10;  failover       &#61; optional&#40;bool, false&#41;&#10;&#125;&#41;&#41;">list&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#91;&#93;</code> |
 | [description](variables.tf#L75) | Optional description used for resources. | <code>string</code> |  | <code>&#34;Terraform managed.&#34;</code> |
 | [global_access](variables.tf#L81) | Global access, defaults to false if not set. | <code>bool</code> |  | <code>null</code> |
diff --git a/modules/net-ilb/main.tf b/modules/net-ilb/main.tf
index 177a7cf5..90a97fed 100644
--- a/modules/net-ilb/main.tf
+++ b/modules/net-ilb/main.tf
@@ -80,11 +80,7 @@ resource "google_compute_region_backend_service" "default" {
         : null
       )
       idle_timeout_sec = local.bs_conntrack.idle_timeout_sec
-      tracking_mode = (
-        local.bs_conntrack.tracking_mode != null
-        ? local.bs_conntrack.tracking_mode
-        : null
-      )
+      tracking_mode = try(local.bs_conntrack.track_per_session ? "PER_SESSION" : "PER_CONNECTION", null)
     }
   }
 
diff --git a/modules/net-ilb/variables.tf b/modules/net-ilb/variables.tf
index 4b942edc..538d10af 100644
--- a/modules/net-ilb/variables.tf
+++ b/modules/net-ilb/variables.tf
@@ -27,7 +27,7 @@ variable "backend_service_config" {
     connection_tracking = optional(object({
       idle_timeout_sec          = optional(number)
       persist_conn_on_unhealthy = optional(string)
-      tracking_mode             = optional(string)
+      track_per_session         = optional(true)
     }))
     enable_subsetting = optional(bool)
     failover_config = optional(object({