tweak

esphome/components/captive_portal/__init__.py

@@ -72,6 +72,16 @@ def _final_validate(config: ConfigType) -> ConfigType:
             "Add 'ap:' to your WiFi configuration to enable the captive portal."
         )
 
+    # Register socket needs for DNS server and additional HTTP connections
+    # - 1 UDP socket for DNS server
+    # - 3 additional TCP sockets for captive portal detection probes + configuration requests
+    #   OS captive portal detection makes multiple probe requests that stay in TIME_WAIT.
+    #   Need headroom for actual user configuration requests.
+    #   LRU purging will reclaim idle sockets to prevent exhaustion from repeated attempts.
+    from esphome.components import socket
+
+    socket.consume_sockets(4, "captive_portal")(config)
+
     return config
 
 

esphome/components/captive_portal/captive_portal.cpp

@@ -13,16 +13,14 @@ static const char *const TAG = "captive_portal";
 void CaptivePortal::handle_config(AsyncWebServerRequest *request) {
   AsyncResponseStream *stream = request->beginResponseStream(ESPHOME_F("application/json"));
   stream->addHeader(ESPHOME_F("cache-control"), ESPHOME_F("public, max-age=0, must-revalidate"));
-  char mac_s[18];
-  const char *mac_str = get_mac_address_pretty_into_buffer(mac_s);
 #ifdef USE_ESP8266
   stream->print(ESPHOME_F("{\"mac\":\""));
-  stream->print(mac_str);
+  stream->print(get_mac_address_pretty().c_str());
   stream->print(ESPHOME_F("\",\"name\":\""));
   stream->print(App.get_name().c_str());
   stream->print(ESPHOME_F("\",\"aps\":[{}"));
 #else
-  stream->printf(R"({"mac":"%s","name":"%s","aps":[{})", mac_str, App.get_name().c_str());
+  stream->printf(R"({"mac":"%s","name":"%s","aps":[{})", get_mac_address_pretty().c_str(), App.get_name().c_str());
 #endif
 
   for (auto &scan : wifi::global_wifi_component->get_scan_result()) {
@@ -52,8 +50,8 @@ void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
   ESP_LOGI(TAG, "Requested WiFi Settings Change:");
   ESP_LOGI(TAG, "  SSID='%s'", ssid.c_str());
   ESP_LOGI(TAG, "  Password=" LOG_SECRET("'%s'"), psk.c_str());
-  wifi::global_wifi_component->save_wifi_sta(ssid, psk);
-  wifi::global_wifi_component->start_scanning();
+  // Defer save to main loop thread to avoid NVS operations from HTTP thread
+  this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid, psk); });
   request->redirect(ESPHOME_F("/?save"));
 }
 
@@ -65,6 +63,12 @@ void CaptivePortal::start() {
   this->base_->init();
   if (!this->initialized_) {
     this->base_->add_handler(this);
+#ifdef USE_ESP32
+    // Enable LRU socket purging to handle captive portal detection probe bursts
+    // OS captive portal detection makes many simultaneous HTTP requests which can
+    // exhaust sockets. LRU purging automatically closes oldest idle connections.
+    this->base_->get_server()->set_lru_purge_enable(true);
+#endif
   }
 
   network::IPAddress ip = wifi::global_wifi_component->wifi_soft_ap_ip();

esphome/components/captive_portal/captive_portal.h

@@ -40,6 +40,10 @@ class CaptivePortal : public AsyncWebHandler, public Component {
   void end() {
     this->active_ = false;
     this->disable_loop();  // Stop processing DNS requests
+#ifdef USE_ESP32
+    // Disable LRU socket purging now that captive portal is done
+    this->base_->get_server()->set_lru_purge_enable(false);
+#endif
     this->base_->deinit();
     if (this->dns_server_ != nullptr) {
       this->dns_server_->stop();

esphome/components/web_server/web_server.cpp

@@ -359,8 +359,8 @@ void WebServer::handle_pna_cors_request(AsyncWebServerRequest *request) {
   AsyncWebServerResponse *response = request->beginResponse(200, "");
   response->addHeader(HEADER_CORS_ALLOW_PNA, "true");
   response->addHeader(HEADER_PNA_NAME, App.get_name().c_str());
-  char mac_s[18];
-  response->addHeader(HEADER_PNA_ID, get_mac_address_pretty_into_buffer(mac_s));
+  std::string mac = get_mac_address_pretty();
+  response->addHeader(HEADER_PNA_ID, mac.c_str());
   request->send(response);
 }
 #endif

esphome/components/web_server_idf/web_server_idf.cpp

@@ -94,6 +94,18 @@ void AsyncWebServer::end() {
   }
 }
 
+void AsyncWebServer::set_lru_purge_enable(bool enable) {
+  if (this->lru_purge_enable_ == enable) {
+    return;  // No change needed
+  }
+  this->lru_purge_enable_ = enable;
+  // If server is already running, restart it with new config
+  if (this->server_) {
+    this->end();
+    this->begin();
+  }
+}
+
 void AsyncWebServer::begin() {
   if (this->server_) {
     this->end();
@@ -101,6 +113,8 @@ void AsyncWebServer::begin() {
   httpd_config_t config = HTTPD_DEFAULT_CONFIG();
   config.server_port = this->port_;
   config.uri_match_fn = [](const char * /*unused*/, const char * /*unused*/, size_t /*unused*/) { return true; };
+  // Enable LRU purging if requested (e.g., by captive portal to handle probe bursts)
+  config.lru_purge_enable = this->lru_purge_enable_;
   if (httpd_start(&this->server_, &config) == ESP_OK) {
     const httpd_uri_t handler_get = {
         .uri = "",
@@ -242,6 +256,7 @@ void AsyncWebServerRequest::send(int code, const char *content_type, const char
 void AsyncWebServerRequest::redirect(const std::string &url) {
   httpd_resp_set_status(*this, "302 Found");
   httpd_resp_set_hdr(*this, "Location", url.c_str());
+  httpd_resp_set_hdr(*this, "Connection", "close");
   httpd_resp_send(*this, nullptr, 0);
 }
 

esphome/components/web_server_idf/web_server_idf.h

@@ -199,9 +199,13 @@ class AsyncWebServer {
     return *handler;
   }
 
+  void set_lru_purge_enable(bool enable);
+  httpd_handle_t get_server() { return this->server_; }
+
  protected:
   uint16_t port_{};
   httpd_handle_t server_{};
+  bool lru_purge_enable_{false};
   static esp_err_t request_handler(httpd_req_t *r);
   static esp_err_t request_post_handler(httpd_req_t *r);
   esp_err_t request_handler_(AsyncWebServerRequest *request) const;

esphome/components/wifi/__init__.py

@@ -69,6 +69,12 @@ CONF_MIN_AUTH_MODE = "min_auth_mode"
 # Limited to 127 because selected_sta_index_ is int8_t in C++
 MAX_WIFI_NETWORKS = 127
 
+# Default AP timeout - allows sufficient time to try all BSSIDs during initial connection
+# After AP starts, WiFi scanning is skipped to avoid disrupting the AP, so we only
+# get best-effort connection attempts. Longer timeout ensures we exhaust all options
+# before falling back to AP mode.
+DEFAULT_AP_TIMEOUT = "2min"
+
 wifi_ns = cg.esphome_ns.namespace("wifi")
 EAPAuth = wifi_ns.struct("EAPAuth")
 ManualIP = wifi_ns.struct("ManualIP")
@@ -177,7 +183,7 @@ CONF_AP_TIMEOUT = "ap_timeout"
 WIFI_NETWORK_AP = WIFI_NETWORK_BASE.extend(
     {
         cv.Optional(
-            CONF_AP_TIMEOUT, default="1min"
+            CONF_AP_TIMEOUT, default=DEFAULT_AP_TIMEOUT
         ): cv.positive_time_period_milliseconds,
     }
 )

esphome/components/wifi/wifi_component.cpp

@@ -199,7 +199,12 @@ static constexpr uint8_t WIFI_RETRY_COUNT_PER_AP = 1;
 
 /// Cooldown duration in milliseconds after adapter restart or repeated failures
 /// Allows WiFi hardware to stabilize before next connection attempt
-static constexpr uint32_t WIFI_COOLDOWN_DURATION_MS = 1000;
+static constexpr uint32_t WIFI_COOLDOWN_DURATION_MS = 500;
+
+/// Cooldown duration when fallback AP is active and captive portal may be running
+/// Longer interval gives users time to configure WiFi without constant connection attempts
+/// While connecting, WiFi can't beacon the AP properly, so needs longer cooldown
+static constexpr uint32_t WIFI_COOLDOWN_WITH_AP_ACTIVE_MS = 30000;
 
 static constexpr uint8_t get_max_retries_for_phase(WiFiRetryPhase phase) {
   switch (phase) {
@@ -334,11 +339,10 @@ void WiFiComponent::setup() {
 }
 
 void WiFiComponent::start() {
-  char mac_s[18];
   ESP_LOGCONFIG(TAG,
                 "Starting\n"
                 "  Local MAC: %s",
-                get_mac_address_pretty_into_buffer(mac_s));
+                get_mac_address_pretty().c_str());
   this->last_connected_ = millis();
 
   uint32_t hash = this->has_sta() ? fnv1_hash(App.get_compilation_time()) : 88491487UL;
@@ -418,10 +422,6 @@ void WiFiComponent::start() {
 void WiFiComponent::restart_adapter() {
   ESP_LOGW(TAG, "Restarting adapter");
   this->wifi_mode_(false, {});
-  // Enter cooldown state to allow WiFi hardware to stabilize after restart
-  // Don't set retry_phase_ or num_retried_ here - state machine handles transitions
-  this->state_ = WIFI_COMPONENT_STATE_COOLDOWN;
-  this->action_started_ = millis();
   this->error_from_callback_ = false;
 }
 
@@ -442,7 +442,10 @@ void WiFiComponent::loop() {
     switch (this->state_) {
       case WIFI_COMPONENT_STATE_COOLDOWN: {
         this->status_set_warning(LOG_STR("waiting to reconnect"));
-        if (now - this->action_started_ > WIFI_COOLDOWN_DURATION_MS) {
+        // Use longer cooldown when captive portal/improv is active to avoid disrupting user config
+        bool portal_active = this->is_captive_portal_active_() || this->is_esp32_improv_active_();
+        uint32_t cooldown_duration = portal_active ? WIFI_COOLDOWN_WITH_AP_ACTIVE_MS : WIFI_COOLDOWN_DURATION_MS;
+        if (now - this->action_started_ > cooldown_duration) {
           // After cooldown we either restarted the adapter because of
           // a failure, or something tried to connect over and over
           // so we entered cooldown. In both cases we call
@@ -667,6 +670,21 @@ void WiFiComponent::save_wifi_sta(const std::string &ssid, const std::string &pa
   sta.set_ssid(ssid);
   sta.set_password(password);
   this->set_sta(sta);
+
+  // Force scan on next attempt even if captive portal is still active
+  // This ensures new credentials are tried with proper BSSID selection after provisioning
+  this->force_scan_after_provision_ = true;
+
+  // Trigger connection attempt (exits cooldown if needed, no-op if already connecting/connected)
+  this->connect_soon_();
+}
+
+void WiFiComponent::connect_soon_() {
+  // Only trigger retry if we're in cooldown - if already connecting/connected, do nothing
+  if (this->state_ == WIFI_COMPONENT_STATE_COOLDOWN) {
+    ESP_LOGD(TAG, "Exiting cooldown early due to new WiFi credentials");
+    this->retry_connect();
+  }
 }
 
 void WiFiComponent::start_connecting(const WiFiAP &ap) {
@@ -801,8 +819,7 @@ void WiFiComponent::print_connect_params_() {
   char bssid_s[18];
   format_mac_addr_upper(bssid.data(), bssid_s);
 
-  char mac_s[18];
-  ESP_LOGCONFIG(TAG, "  Local MAC: %s", get_mac_address_pretty_into_buffer(mac_s));
+  ESP_LOGCONFIG(TAG, "  Local MAC: %s", get_mac_address_pretty().c_str());
   if (this->is_disabled()) {
     ESP_LOGCONFIG(TAG, "  Disabled");
     return;
@@ -866,6 +883,8 @@ void WiFiComponent::start_scanning() {
   ESP_LOGD(TAG, "Starting scan");
   this->wifi_scan_start_(this->passive_scan_);
   this->state_ = WIFI_COMPONENT_STATE_STA_SCANNING;
+  // Clear the force scan flag after starting the scan
+  this->force_scan_after_provision_ = false;
 }
 
 /// Comparator for WiFi scan result sorting - determines which network should be tried first
@@ -1231,9 +1250,18 @@ WiFiRetryPhase WiFiComponent::determine_next_phase_() {
       return WiFiRetryPhase::RESTARTING_ADAPTER;
 
     case WiFiRetryPhase::RESTARTING_ADAPTER:
-      // After restart, go back to explicit hidden if we went through it initially, otherwise scan
-      return this->went_through_explicit_hidden_phase_() ? WiFiRetryPhase::EXPLICIT_HIDDEN
-                                                         : WiFiRetryPhase::SCAN_CONNECTING;
+      // After restart, go back to explicit hidden if we went through it initially
+      if (this->went_through_explicit_hidden_phase_()) {
+        return WiFiRetryPhase::EXPLICIT_HIDDEN;
+      }
+      // Skip scanning when captive portal/improv is active to avoid disrupting AP
+      // Even passive scans can cause brief AP disconnections on ESP32
+      // UNLESS new credentials were just provisioned - then we need to scan
+      if ((this->is_captive_portal_active_() || this->is_esp32_improv_active_()) &&
+          !this->force_scan_after_provision_) {
+        return WiFiRetryPhase::RETRY_HIDDEN;
+      }
+      return WiFiRetryPhase::SCAN_CONNECTING;
   }
 
   // Should never reach here
@@ -1321,6 +1349,10 @@ bool WiFiComponent::transition_to_phase_(WiFiRetryPhase new_phase) {
       if (!this->is_captive_portal_active_() && !this->is_esp32_improv_active_()) {
         this->restart_adapter();
       }
+      // Always enter cooldown after restart (or skip-restart) to allow stabilization
+      // Use extended cooldown when AP is active to avoid constant scanning that blocks DNS
+      this->state_ = WIFI_COMPONENT_STATE_COOLDOWN;
+      this->action_started_ = millis();
       // Return true to indicate we should wait (go to COOLDOWN) instead of immediately connecting
       return true;
 

esphome/components/wifi/wifi_component.h

@@ -291,6 +291,7 @@ class WiFiComponent : public Component {
   void set_passive_scan(bool passive);
 
   void save_wifi_sta(const std::string &ssid, const std::string &password);
+
   // ========== INTERNAL METHODS ==========
   // (In most use cases you won't need these)
   /// Setup WiFi interface.
@@ -424,6 +425,8 @@ class WiFiComponent : public Component {
     return true;
   }
 
+  void connect_soon_();
+
   void wifi_loop_();
   bool wifi_mode_(optional<bool> sta, optional<bool> ap);
   bool wifi_sta_pre_setup_();
@@ -529,6 +532,7 @@ class WiFiComponent : public Component {
   bool enable_on_boot_;
   bool got_ipv4_address_{false};
   bool keep_scan_results_{false};
+  bool force_scan_after_provision_{false};
 
   // Pointers at the end (naturally aligned)
   Trigger<> *connect_trigger_{new Trigger<>()};

esphome/components/wifi_info/wifi_info_text_sensor.h

@@ -126,10 +126,7 @@ class BSSIDWiFiInfo : public PollingComponent, public text_sensor::TextSensor {
 
 class MacAddressWifiInfo : public Component, public text_sensor::TextSensor {
  public:
-  void setup() override {
-    char mac_s[18];
-    this->publish_state(get_mac_address_pretty_into_buffer(mac_s));
-  }
+  void setup() override { this->publish_state(get_mac_address_pretty()); }
   void dump_config() override;
 };
 

esphome/core/helpers.cpp

@@ -638,8 +638,9 @@ std::string get_mac_address() {
 }
 
 std::string get_mac_address_pretty() {
-  char buf[18];
-  return std::string(get_mac_address_pretty_into_buffer(buf));
+  uint8_t mac[6];
+  get_mac_address_raw(mac);
+  return format_mac_address_pretty(mac);
 }
 
 void get_mac_address_into_buffer(std::span<char, 13> buf) {
@@ -648,13 +649,6 @@ void get_mac_address_into_buffer(std::span<char, 13> buf) {
   format_mac_addr_lower_no_sep(mac, buf.data());
 }
 
-const char *get_mac_address_pretty_into_buffer(std::span<char, 18> buf) {
-  uint8_t mac[6];
-  get_mac_address_raw(mac);
-  format_mac_addr_upper(mac, buf.data());
-  return buf.data();
-}
-
 #ifndef USE_ESP32
 bool has_custom_mac_address() { return false; }
 #endif

esphome/core/helpers.h

@@ -1052,11 +1052,6 @@ std::string get_mac_address_pretty();
 /// Assumes buffer length is 13 (12 digits for hexadecimal representation followed by null terminator).
 void get_mac_address_into_buffer(std::span<char, 13> buf);
 
-/// Get the device MAC address into the given buffer, in colon-separated uppercase hex notation.
-/// Buffer must be exactly 18 bytes (17 for "XX:XX:XX:XX:XX:XX" + null terminator).
-/// Returns pointer to the buffer for convenience.
-const char *get_mac_address_pretty_into_buffer(std::span<char, 18> buf);
-
 #ifdef USE_ESP32
 /// Set the MAC address to use from the provided byte array (6 bytes).
 void set_mac_address(uint8_t *mac);