diff --git a/config/env.example.optional b/config/env.example.optional
index 371df1072..c79ce23bb 100644
--- a/config/env.example.optional
+++ b/config/env.example.optional
@@ -244,9 +244,11 @@ REDIS_SIDEKIQ_MASTER='master_name'
 REDIS_SIDEKIQ_PASSWORD='sentinel_and_redis_password'
 REDIS_SIDEKIQ_USERNAME='sentinel_and_redis_username'
 
-# configuration for prometheus metrics web server
+# configuration for prometheus metrics web server on /metrics
 # launched with sidekiq and puma
-PROMETHEUS_EXPORTER_BIND="0.0.0.0"
+# adjust according to your prometheus probe, 127.0.0.1 or your local/admin net address
+# it's advised to avoid 0.0.0.0 or if you do, please configure ACL elsewhere (webserver, reverse proxy, ...)
+PROMETHEUS_EXPORTER_BIND="127.0.0.1"
 PROMETHEUS_EXPORTER_PORT="9394"
 PROMETHEUS_EXPORTER_ENABLED="disabled"