diff --git a/framework/src/android/net/ConnectivitySettingsManager.java b/framework/src/android/net/ConnectivitySettingsManager.java
index ba7df7ff9b102624a2b2a5dc8fa05b43b8eef7f6..f3758c54c59921512b3bd73892031529f0616ef1 100644
--- a/framework/src/android/net/ConnectivitySettingsManager.java
+++ b/framework/src/android/net/ConnectivitySettingsManager.java
@@ -356,6 +356,12 @@ public class ConnectivitySettingsManager {
      */
     public static final int PRIVATE_DNS_MODE_OFF = ConnectivitySettingsUtils.PRIVATE_DNS_MODE_OFF;
 
+    /**
+     * @hide
+     */
+    public static final int PRIVATE_DNS_MODE_QUADNINE =
+            ConnectivitySettingsUtils.PRIVATE_DNS_MODE_QUADNINE;
+
     /**
      * One of the private DNS modes that indicates the private DNS mode is automatic, which
      * will try to use the current DNS as private DNS.
@@ -371,10 +377,17 @@ public class ConnectivitySettingsManager {
     public static final int PRIVATE_DNS_MODE_PROVIDER_HOSTNAME =
             ConnectivitySettingsUtils.PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
 
+    /**
+     * @hide
+     */
+    public static final String PRIVATE_DNS_SPECIFIER_QUADNINE = "dns.quad9.net";
+
+
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
     @IntDef(value = {
             PRIVATE_DNS_MODE_OFF,
+            PRIVATE_DNS_MODE_QUADNINE,
             PRIVATE_DNS_MODE_OPPORTUNISTIC,
             PRIVATE_DNS_MODE_PROVIDER_HOSTNAME,
     })
@@ -829,6 +842,7 @@ public class ConnectivitySettingsManager {
     public static void setPrivateDnsDefaultMode(@NonNull Context context,
             @NonNull @PrivateDnsMode int mode) {
         if (!(mode == PRIVATE_DNS_MODE_OFF
+                || mode == PRIVATE_DNS_MODE_QUADNINE
                 || mode == PRIVATE_DNS_MODE_OPPORTUNISTIC
                 || mode == PRIVATE_DNS_MODE_PROVIDER_HOSTNAME)) {
             throw new IllegalArgumentException("Invalid private dns mode");
diff --git a/service/src/com/android/server/connectivity/DnsManager.java b/service/src/com/android/server/connectivity/DnsManager.java
index c940eecd4638f709839231a5edf5ef2430c5ece6..20f2e9bf98e9ba7d5f9c9dd518d7804b622ed484 100644
--- a/service/src/com/android/server/connectivity/DnsManager.java
+++ b/service/src/com/android/server/connectivity/DnsManager.java
@@ -23,8 +23,10 @@ import static android.net.ConnectivitySettingsManager.DNS_RESOLVER_SUCCESS_THRES
 import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_DEFAULT_MODE;
 import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_MODE;
 import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_MODE_OFF;
+import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_MODE_QUADNINE;
 import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
 import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_SPECIFIER;
+import static android.net.ConnectivitySettingsManager.PRIVATE_DNS_SPECIFIER_QUADNINE;
 import static android.net.resolv.aidl.IDnsResolverUnsolicitedEventListener.VALIDATION_RESULT_FAILURE;
 import static android.net.resolv.aidl.IDnsResolverUnsolicitedEventListener.VALIDATION_RESULT_SUCCESS;
 
@@ -145,6 +147,10 @@ public class DnsManager {
             return new PrivateDnsConfig(specifier, null);
         }
 
+        if (PRIVATE_DNS_MODE_QUADNINE == mode) {
+            return new PrivateDnsConfig(PRIVATE_DNS_SPECIFIER_QUADNINE, null);
+        }
+
         return new PrivateDnsConfig(useTls);
     }
 
diff --git a/staticlibs/framework/com/android/net/module/util/ConnectivitySettingsUtils.java b/staticlibs/framework/com/android/net/module/util/ConnectivitySettingsUtils.java
index f4856b344fd47300fb72586c9734ba784e46c70b..08619fe3e27af849789ec5f3349ad5f4054da898 100644
--- a/staticlibs/framework/com/android/net/module/util/ConnectivitySettingsUtils.java
+++ b/staticlibs/framework/com/android/net/module/util/ConnectivitySettingsUtils.java
@@ -32,10 +32,12 @@ public class ConnectivitySettingsUtils {
     public static final int PRIVATE_DNS_MODE_OFF = 1;
     public static final int PRIVATE_DNS_MODE_OPPORTUNISTIC = 2;
     public static final int PRIVATE_DNS_MODE_PROVIDER_HOSTNAME = 3;
+    public static final int PRIVATE_DNS_MODE_QUADNINE = 4;
 
     public static final String PRIVATE_DNS_DEFAULT_MODE = "private_dns_default_mode";
     public static final String PRIVATE_DNS_MODE = "private_dns_mode";
     public static final String PRIVATE_DNS_MODE_OFF_STRING = "off";
+    public static final String PRIVATE_DNS_MODE_QUADNINE_STRING = "quadnine";
     public static final String PRIVATE_DNS_MODE_OPPORTUNISTIC_STRING = "opportunistic";
     public static final String PRIVATE_DNS_MODE_PROVIDER_HOSTNAME_STRING = "hostname";
     public static final String PRIVATE_DNS_SPECIFIER = "private_dns_specifier";
@@ -50,6 +52,8 @@ public class ConnectivitySettingsUtils {
         switch (mode) {
             case PRIVATE_DNS_MODE_OFF:
                 return PRIVATE_DNS_MODE_OFF_STRING;
+            case PRIVATE_DNS_MODE_QUADNINE:
+                return PRIVATE_DNS_MODE_QUADNINE_STRING;
             case PRIVATE_DNS_MODE_OPPORTUNISTIC:
                 return PRIVATE_DNS_MODE_OPPORTUNISTIC_STRING;
             case PRIVATE_DNS_MODE_PROVIDER_HOSTNAME:
@@ -67,6 +71,8 @@ public class ConnectivitySettingsUtils {
         switch (mode) {
             case "off":
                 return PRIVATE_DNS_MODE_OFF;
+            case "quadnine":
+                return PRIVATE_DNS_MODE_QUADNINE;
             case "hostname":
                 return PRIVATE_DNS_MODE_PROVIDER_HOSTNAME;
             case "opportunistic":
@@ -100,6 +106,7 @@ public class ConnectivitySettingsUtils {
      */
     public static void setPrivateDnsMode(@NonNull Context context, int mode) {
         if (!(mode == PRIVATE_DNS_MODE_OFF
+                || mode == PRIVATE_DNS_MODE_QUADNINE
                 || mode == PRIVATE_DNS_MODE_OPPORTUNISTIC
                 || mode == PRIVATE_DNS_MODE_PROVIDER_HOSTNAME)) {
             throw new IllegalArgumentException("Invalid private dns mode: " + mode);