diff --git a/server/FirewallController.cpp b/server/FirewallController.cpp
index 0a0f8d8..35fd1e2 100644
--- a/server/FirewallController.cpp
+++ b/server/FirewallController.cpp
@@ -90,7 +90,8 @@
 }
 
 int FirewallController::setupIptablesHooks(void) {
-    int res = 0;
+    int res = flushRules();
+
     // mUseBpfOwnerMatch should be removed, but it is still depended upon by test code.
     mUseBpfOwnerMatch = true;
     if (mUseBpfOwnerMatch) {
@@ -126,19 +127,22 @@
     return res ? -EREMOTEIO : 0;
 }
 
+int FirewallController::flushRules() {
+    std::string command =
+            "*filter\n"
+            ":fw_INPUT -\n"
+            ":fw_OUTPUT -\n"
+            ":fw_FORWARD -\n"
+            "-6 -A fw_OUTPUT ! -o lo -s ::1 -j DROP\n"
+            "COMMIT\n";
+
+    return (execIptablesRestore(V4V6, command.c_str()) == 0) ? 0 : -EREMOTEIO;
+}
+
 int FirewallController::resetFirewall(void) {
     mFirewallType = ALLOWLIST;
     mIfaceRules.clear();
-
-    // flush any existing rules
-    std::string command =
-        "*filter\n"
-        ":fw_INPUT -\n"
-        ":fw_OUTPUT -\n"
-        ":fw_FORWARD -\n"
-        "COMMIT\n";
-
-    return (execIptablesRestore(V4V6, command.c_str()) == 0) ? 0 : -EREMOTEIO;
+    return flushRules();
 }
 
 int FirewallController::enableChildChains(ChildChain chain, bool enable) {
diff --git a/server/FirewallController.h b/server/FirewallController.h
index 6cabfb5..6de1b45 100644
--- a/server/FirewallController.h
+++ b/server/FirewallController.h
@@ -57,46 +57,46 @@
  */
 class FirewallController {
 public:
-    FirewallController();
+  FirewallController();
 
-    int setupIptablesHooks(void);
+  int setupIptablesHooks(void);
 
-    int setFirewallType(FirewallType);
-    int resetFirewall(void);
-    int isFirewallEnabled(void);
+  int setFirewallType(FirewallType);
+  int resetFirewall(void);
+  int isFirewallEnabled(void);
 
-    /* Match traffic going in/out over the given iface. */
-    int setInterfaceRule(const char*, FirewallRule);
-    /* Match traffic owned by given UID. This is specific to a particular chain. */
-    int setUidRule(ChildChain, int, FirewallRule);
+  /* Match traffic going in/out over the given iface. */
+  int setInterfaceRule(const char*, FirewallRule);
+  /* Match traffic owned by given UID. This is specific to a particular chain. */
+  int setUidRule(ChildChain, int, FirewallRule);
 
-    int enableChildChains(ChildChain, bool);
+  int enableChildChains(ChildChain, bool);
 
-    int replaceUidChain(const std::string&, bool, const std::vector<int32_t>&);
+  int replaceUidChain(const std::string&, bool, const std::vector<int32_t>&);
 
-    static std::string makeCriticalCommands(IptablesTarget target, const char* chainName);
-    static uid_t discoverMaximumValidUid(const std::string& fileName);
+  static std::string makeCriticalCommands(IptablesTarget target, const char* chainName);
+  static uid_t discoverMaximumValidUid(const std::string& fileName);
 
-    static const char* TABLE;
+  static const char* TABLE;
 
-    static const char* LOCAL_INPUT;
-    static const char* LOCAL_OUTPUT;
-    static const char* LOCAL_FORWARD;
+  static const char* LOCAL_INPUT;
+  static const char* LOCAL_OUTPUT;
+  static const char* LOCAL_FORWARD;
 
-    static const char* LOCAL_DOZABLE;
-    static const char* LOCAL_STANDBY;
-    static const char* LOCAL_POWERSAVE;
-    static const char* LOCAL_RESTRICTED;
+  static const char* LOCAL_DOZABLE;
+  static const char* LOCAL_STANDBY;
+  static const char* LOCAL_POWERSAVE;
+  static const char* LOCAL_RESTRICTED;
 
-    static const char* ICMPV6_TYPES[];
+  static const char* ICMPV6_TYPES[];
 
-    std::mutex lock;
+  std::mutex lock;
 
 protected:
-    friend class FirewallControllerTest;
-    std::string makeUidRules(IptablesTarget target, const char* name, bool isAllowlist,
-                             const std::vector<int32_t>& uids);
-    static int (*execIptablesRestore)(IptablesTarget target, const std::string& commands);
+  friend class FirewallControllerTest;
+  std::string makeUidRules(IptablesTarget target, const char* name, bool isAllowlist,
+                           const std::vector<int32_t>& uids);
+  static int (*execIptablesRestore)(IptablesTarget target, const std::string& commands);
 
 private:
   // Netd supports two cases, in both of which mMaxUid that derives from the uid mapping is const:
@@ -108,6 +108,7 @@
   FirewallType mFirewallType;
   bool mUseBpfOwnerMatch;
   std::set<std::string> mIfaceRules;
+  int flushRules(void);
   int attachChain(const char*, const char*);
   int detachChain(const char*, const char*);
   int createChain(const char*, FirewallType);
diff --git a/server/FirewallControllerTest.cpp b/server/FirewallControllerTest.cpp
index df6ca82..1f199af 100644
--- a/server/FirewallControllerTest.cpp
+++ b/server/FirewallControllerTest.cpp
@@ -227,19 +227,18 @@
 
 TEST_F(FirewallControllerTest, TestFirewall) {
     std::vector<std::string> enableCommands = {
-        "*filter\n"
-        "-A fw_INPUT -j DROP\n"
-        "-A fw_OUTPUT -j REJECT\n"
-        "-A fw_FORWARD -j REJECT\n"
-        "COMMIT\n"
-    };
+            "*filter\n"
+            "-A fw_INPUT -j DROP\n"
+            "-A fw_OUTPUT -j REJECT\n"
+            "-A fw_FORWARD -j REJECT\n"
+            "COMMIT\n"};
     std::vector<std::string> disableCommands = {
-        "*filter\n"
-        ":fw_INPUT -\n"
-        ":fw_OUTPUT -\n"
-        ":fw_FORWARD -\n"
-        "COMMIT\n"
-    };
+            "*filter\n"
+            ":fw_INPUT -\n"
+            ":fw_OUTPUT -\n"
+            ":fw_FORWARD -\n"
+            "-6 -A fw_OUTPUT ! -o lo -s ::1 -j DROP\n"
+            "COMMIT\n"};
     std::vector<std::string> noCommands = {};
 
     EXPECT_EQ(0, mFw.resetFirewall());
diff --git a/tests/binder_test.cpp b/tests/binder_test.cpp
index 22d1f22..e80296a 100644
--- a/tests/binder_test.cpp
+++ b/tests/binder_test.cpp
@@ -2420,11 +2420,14 @@
 }
 
 void expectFirewallDenylistMode() {
-    for (const auto& binary : {IPTABLES_PATH, IP6TABLES_PATH}) {
-        EXPECT_EQ(2, iptablesRuleLineLength(binary, FIREWALL_INPUT));
-        EXPECT_EQ(2, iptablesRuleLineLength(binary, FIREWALL_OUTPUT));
-        EXPECT_EQ(2, iptablesRuleLineLength(binary, FIREWALL_FORWARD));
-    }
+    EXPECT_EQ(2, iptablesRuleLineLength(IPTABLES_PATH, FIREWALL_INPUT));
+    EXPECT_EQ(2, iptablesRuleLineLength(IPTABLES_PATH, FIREWALL_OUTPUT));
+    EXPECT_EQ(2, iptablesRuleLineLength(IPTABLES_PATH, FIREWALL_FORWARD));
+
+    // for IPv6 there is an extra OUTPUT rule to DROP ::1 sourced packets to non-loopback devices
+    EXPECT_EQ(2, iptablesRuleLineLength(IP6TABLES_PATH, FIREWALL_INPUT));
+    EXPECT_EQ(3, iptablesRuleLineLength(IP6TABLES_PATH, FIREWALL_OUTPUT));
+    EXPECT_EQ(2, iptablesRuleLineLength(IP6TABLES_PATH, FIREWALL_FORWARD));
 }
 
 bool iptablesFirewallInterfaceFirstRuleExists(const char* binary, const char* chainName,