diff --git a/source/_integrations/zeroconf.markdown b/source/_integrations/zeroconf.markdown
index a578cd77ac1..d157bdf589b 100644
--- a/source/_integrations/zeroconf.markdown
+++ b/source/_integrations/zeroconf.markdown
@@ -30,7 +30,7 @@ zeroconf:
   type: map
   keys:
    default_interface:
-     description: By default, `zeroconf` will broadcast on the default interface. For systems that require broadcasting `mdns` on all interfaces, change this option to `false` if `zeroconf` does not function.
+     description: By default, `zeroconf` will attempt to detect the best value based on available routing information. For systems that require broadcasting mDNS on all interfaces, change this option to `false` if `zeroconf` does not function.
      required: false
      type: boolean
      default: true
@@ -40,3 +40,12 @@ zeroconf:
      type: boolean
      default: true
 {% endconfiguration %}
+
+## `default_interface` auto detection
+
+If the `default_interface` is unset, the value is auto-detected based on the system routing next hop for the mDNS broadcast address (`224.0.0.251`).
+
+If the next-hop cannot be detected or is a loopback address, `zeroconf` will broadcast on all interfaces. If the next hop is a non-loopback address, `zeroconf` will only broadcast on the default interface.
+
+Setting the `default_interface` to `true` or `false` will override the auto detection.
+