diff --git a/docs/releaseNotes.yml b/docs/releaseNotes.yml
index b2fd29cde8..06263e2eca 100644
--- a/docs/releaseNotes.yml
+++ b/docs/releaseNotes.yml
@@ -53,6 +53,13 @@ items:
           Support for the Envoy V2 API and the `AMBASSADOR_ENVOY_API_VERSION` environment
           variable have been removed. Only the Envoy V3 API is supported (this has been the
           default since Emissary-ingress v1.14.0).
+
+      - title: DiagD internal tcp idle timeout tuning
+        type: change
+        body: >-
+          Set the diagd tcp idle timeout (i.e. keepalive timeout) to 300s, up from the
+          gunicorn default of 2s. This should help eliminate race-conditions where
+          probing `/ambassador/v0/check_alive` may intermittently fail.
  
   - version: 2.1.0
     date: '2021-12-16'
diff --git a/python/ambassador_diag/diagd.py b/python/ambassador_diag/diagd.py
index 3ab13f876b..403fa07f65 100644
--- a/python/ambassador_diag/diagd.py
+++ b/python/ambassador_diag/diagd.py
@@ -2162,6 +2162,7 @@ def _main(snapshot_path=None, bootstrap_path=None, ads_path=None,
         'bind': '%s:%s' % (host, port),
         # 'workers': 1,
         'threads': workers,
+        'keepalive': 300,
     }
 
     app.logger.info("thread count %d, listening on %s" % (gunicorn_config['threads'], gunicorn_config['bind']))