--- a/testing/geckodriver/src/prefs.rs
+++ b/testing/geckodriver/src/prefs.rs
@@ -1,12 +1,12 @@
 use mozprofile::preferences::Pref;
 
 lazy_static! {
-    pub static ref DEFAULT: [(&'static str, Pref); 79] = [
+    pub static ref DEFAULT: [(&'static str, Pref); 80] = [
         // Disable automatic downloading of new releases
         ("app.update.auto", Pref::new(false)),
 
         // Disable automatically upgrading Firefox
         ("app.update.enabled", Pref::new(false)),
 
         // Increase the APZ content response timeout in tests to 1
         // minute.  This is to accommodate the fact that test environments
@@ -141,16 +141,20 @@ lazy_static! {
         // don't block add-ons for e10s
         ("extensions.e10sBlocksEnabling", Pref::new(false)),
 
         // Disable metadata caching for installed add-ons by default
         ("extensions.getAddons.cache.enabled", Pref::new(false)),
 
         // Disable intalling any distribution extensions or add-ons
         ("extensions.installDistroAddons", Pref::new(false)),
+
+        // Make sure Shield doesn't hit the network.
+        ("extensions.shield-recipe-client.api_url", Pref::new("")),
+
         ("extensions.showMismatchUI", Pref::new(false)),
 
         // Turn off extension updates so they do not bother tests
         ("extensions.update.enabled", Pref::new(false)),
         ("extensions.update.notifyUser", Pref::new(false)),
 
         // Make sure opening about:addons will not hit the network
         ("extensions.webservice.discoverURL", Pref::new("http://%(server)s/dummy/discoveryURL")),

--- a/testing/marionette/client/marionette_driver/geckoinstance.py
+++ b/testing/marionette/client/marionette_driver/geckoinstance.py
@@ -43,16 +43,18 @@ class GeckoInstance(object):
         "extensions.autoDisableScopes": 0,
         "extensions.enabledScopes": 5,
         # don't block add-ons for e10s
         "extensions.e10sBlocksEnabling": False,
         # Disable metadata caching for installed add-ons by default
         "extensions.getAddons.cache.enabled": False,
         # Disable intalling any distribution add-ons
         "extensions.installDistroAddons": False,
+        # Make sure Shield doesn't hit the network.
+        "extensions.shield-recipe-client.api_url": "",
         "extensions.showMismatchUI": False,
         # Turn off extension updates so they don't bother tests
         "extensions.update.enabled": False,
         "extensions.update.notifyUser": False,
         # Make sure opening about:addons won"t hit the network
         "extensions.webservice.discoverURL": "http://%(server)s/dummy/discoveryURL",
 
         # Allow the application to have focus even it runs in the background

--- a/testing/marionette/server.js
+++ b/testing/marionette/server.js
@@ -201,19 +201,23 @@ const RECOMMENDED_PREFS = new Map([
   ["extensions.enabledScopes", 5],
 
   // Do not block add-ons for e10s
   ["extensions.e10sBlocksEnabling", false],
 
   // Disable metadata caching for installed add-ons by default
   ["extensions.getAddons.cache.enabled", false],
 
-  // Disable intalling any distribution extensions or add-ons.
+  // Disable installing any distribution extensions or add-ons.
   // Should be set in profile.
   ["extensions.installDistroAddons", false],
+
+  // Make sure Shield doesn't hit the network.
+  ["extensions.shield-recipe-client.api_url", ""],
+
   ["extensions.showMismatchUI", false],
 
   // Turn off extension updates so they do not bother tests
   ["extensions.update.enabled", false],
   ["extensions.update.notifyUser", false],
 
   // Make sure opening about:addons will not hit the network
   [