diff --git a/homeassistant/auth/providers/trusted_networks.py b/homeassistant/auth/providers/trusted_networks.py
new file mode 100644
index 00000000000..7a4b0126505
--- /dev/null
+++ b/homeassistant/auth/providers/trusted_networks.py
@@ -0,0 +1,125 @@
+"""Trusted Networks auth provider.
+
+It shows list of users if access from trusted network.
+Abort login flow if not access from trusted network.
+"""
+import voluptuous as vol
+
+from homeassistant import data_entry_flow
+from homeassistant.core import callback
+from homeassistant.exceptions import HomeAssistantError
+from . import AuthProvider, AUTH_PROVIDER_SCHEMA, AUTH_PROVIDERS
+
+CONFIG_SCHEMA = AUTH_PROVIDER_SCHEMA.extend({
+}, extra=vol.PREVENT_EXTRA)
+
+
+class InvalidAuthError(HomeAssistantError):
+    """Raised when try to access from untrusted networks."""
+
+
+class InvalidUserError(HomeAssistantError):
+    """Raised when try to login as invalid user."""
+
+
+@AUTH_PROVIDERS.register('trusted_networks')
+class TrustedNetworksAuthProvider(AuthProvider):
+    """Trusted Networks auth provider.
+
+    Allow passwordless access from trusted network.
+    """
+
+    DEFAULT_TITLE = 'Trusted Networks'
+
+    async def async_credential_flow(self, context):
+        """Return a flow to login."""
+        users = await self.store.async_get_users()
+        available_users = {user.id: user.name
+                           for user in users
+                           if not user.system_generated and user.is_active}
+
+        return LoginFlow(self, context.get('ip_address'), available_users)
+
+    async def async_get_or_create_credentials(self, flow_result):
+        """Get credentials based on the flow result."""
+        user_id = flow_result['user']
+
+        users = await self.store.async_get_users()
+        for user in users:
+            if (not user.system_generated and
+                    user.is_active and
+                    user.id == user_id):
+                for credential in await self.async_credentials():
+                    if credential.data['user_id'] == user_id:
+                        return credential
+                cred = self.async_create_credentials({'user_id': user_id})
+                await self.store.async_link_user(user, cred)
+                return cred
+
+        # We only allow login as exist user
+        raise InvalidUserError
+
+    async def async_user_meta_for_credentials(self, credentials):
+        """Return extra user metadata for credentials.
+
+        Trusted network auth provider should never create new user.
+        """
+        raise NotImplementedError
+
+    @callback
+    def async_validate_access(self, ip_address):
+        """Make sure the access from trusted networks.
+
+        Raise InvalidAuthError if not.
+        Raise InvalidAuthError if trusted_networks is not config
+        """
+        if (not hasattr(self.hass, 'http') or
+                not self.hass.http or not self.hass.http.trusted_networks):
+            raise InvalidAuthError('trusted_networks is not configured')
+
+        if not any(ip_address in trusted_network for trusted_network
+                   in self.hass.http.trusted_networks):
+            raise InvalidAuthError('Not in trusted_networks')
+
+
+class LoginFlow(data_entry_flow.FlowHandler):
+    """Handler for the login flow."""
+
+    def __init__(self, auth_provider, ip_address, available_users):
+        """Initialize the login flow."""
+        self._auth_provider = auth_provider
+        self._available_users = available_users
+        self._ip_address = ip_address
+
+    async def async_step_init(self, user_input=None):
+        """Handle the step of the form."""
+        errors = {}
+        try:
+            self._auth_provider.async_validate_access(self._ip_address)
+
+        except InvalidAuthError:
+            errors['base'] = 'invalid_auth'
+            return self.async_show_form(
+                step_id='init',
+                data_schema=None,
+                errors=errors,
+            )
+
+        if user_input is not None:
+            user_id = user_input['user']
+            if user_id not in self._available_users:
+                errors['base'] = 'invalid_auth'
+
+            if not errors:
+                return self.async_create_entry(
+                    title=self._auth_provider.name,
+                    data=user_input
+                )
+
+        schema = {'user': vol.In(self._available_users)}
+
+        return self.async_show_form(
+            step_id='init',
+            data_schema=vol.Schema(schema),
+            errors=errors,
+        )
diff --git a/homeassistant/components/auth/login_flow.py b/homeassistant/components/auth/login_flow.py
index 7b80e52a8d7..e1d21bbb632 100644
--- a/homeassistant/components/auth/login_flow.py
+++ b/homeassistant/components/auth/login_flow.py
@@ -63,6 +63,7 @@ import aiohttp.web
 import voluptuous as vol
 
 from homeassistant import data_entry_flow
+from homeassistant.components.http import KEY_REAL_IP
 from homeassistant.components.http.ban import process_wrong_login, \
     log_invalid_auth
 from homeassistant.components.http.data_validator import RequestDataValidator
@@ -151,7 +152,8 @@ class LoginFlowIndexView(HomeAssistantView):
             handler = data['handler']
 
         try:
-            result = await self._flow_mgr.async_init(handler, context={})
+            result = await self._flow_mgr.async_init(
+                handler, context={'ip_address': request[KEY_REAL_IP]})
         except data_entry_flow.UnknownHandler:
             return self.json_message('Invalid handler specified', 404)
         except data_entry_flow.UnknownStep:
@@ -188,6 +190,13 @@ class LoginFlowResourceView(HomeAssistantView):
             return self.json_message('Invalid client id', 400)
 
         try:
+            # do not allow change ip during login flow
+            for flow in self._flow_mgr.async_progress():
+                if (flow['flow_id'] == flow_id and
+                        flow['context']['ip_address'] !=
+                        request.get(KEY_REAL_IP)):
+                    return self.json_message('IP address changed', 400)
+
             result = await self._flow_mgr.async_configure(flow_id, data)
         except data_entry_flow.UnknownFlow:
             return self.json_message('Invalid flow specified', 404)
diff --git a/homeassistant/components/http/__init__.py b/homeassistant/components/http/__init__.py
index c1d80667983..2fbfa099209 100644
--- a/homeassistant/components/http/__init__.py
+++ b/homeassistant/components/http/__init__.py
@@ -220,6 +220,7 @@ class HomeAssistantHTTP:
         self.ssl_key = ssl_key
         self.server_host = server_host
         self.server_port = server_port
+        self.trusted_networks = trusted_networks
         self.is_ban_enabled = is_ban_enabled
         self._handler = None
         self.server = None
diff --git a/homeassistant/components/websocket_api.py b/homeassistant/components/websocket_api.py
index d9c92fa357f..2a1e808188a 100644
--- a/homeassistant/components/websocket_api.py
+++ b/homeassistant/components/websocket_api.py
@@ -344,7 +344,10 @@ class ActiveConnection:
             if request[KEY_AUTHENTICATED]:
                 authenticated = True
 
-            else:
+            # always request auth when auth is active
+            #   even request passed pre-authentication (trusted networks)
+            # or when using legacy api_password
+            if self.hass.auth.active or not authenticated:
                 self.debug("Request auth")
                 await self.wsock.send_json(auth_required_message())
                 msg = await wsock.receive_json()
diff --git a/tests/auth/providers/test_legacy_api_password.py b/tests/auth/providers/test_legacy_api_password.py
index 71642bd7a32..0c129088c8b 100644
--- a/tests/auth/providers/test_legacy_api_password.py
+++ b/tests/auth/providers/test_legacy_api_password.py
@@ -63,18 +63,9 @@ async def test_verify_not_load(hass, provider):
 
 
 async def test_verify_login(hass, provider):
-    """Test we raise if http module not load."""
+    """Test login using legacy api password auth provider."""
     hass.http = Mock(api_password='test-password')
     provider.async_validate_login('test-password')
     hass.http = Mock(api_password='test-password')
     with pytest.raises(legacy_api_password.InvalidAuthError):
         provider.async_validate_login('invalid-password')
-
-
-async def test_utf_8_username_password(provider):
-    """Test that we create a new credential."""
-    credentials = await provider.async_get_or_create_credentials({
-        'username': '🎉',
-        'password': '😎',
-    })
-    assert credentials.is_new is True
diff --git a/tests/auth/providers/test_trusted_networks.py b/tests/auth/providers/test_trusted_networks.py
new file mode 100644
index 00000000000..ca8b5bd90a2
--- /dev/null
+++ b/tests/auth/providers/test_trusted_networks.py
@@ -0,0 +1,106 @@
+"""Test the Trusted Networks auth provider."""
+from unittest.mock import Mock
+
+import pytest
+import voluptuous as vol
+
+from homeassistant import auth
+from homeassistant.auth import auth_store
+from homeassistant.auth.providers import trusted_networks as tn_auth
+
+
+@pytest.fixture
+def store(hass):
+    """Mock store."""
+    return auth_store.AuthStore(hass)
+
+
+@pytest.fixture
+def provider(hass, store):
+    """Mock provider."""
+    return tn_auth.TrustedNetworksAuthProvider(hass, store, {
+        'type': 'trusted_networks'
+    })
+
+
+@pytest.fixture
+def manager(hass, store, provider):
+    """Mock manager."""
+    return auth.AuthManager(hass, store, {
+        (provider.type, provider.id): provider
+    })
+
+
+async def test_trusted_networks_credentials(manager, provider):
+    """Test trusted_networks credentials related functions."""
+    owner = await manager.async_create_user("test-owner")
+    tn_owner_cred = await provider.async_get_or_create_credentials({
+        'user': owner.id
+    })
+    assert tn_owner_cred.is_new is False
+    assert any(cred.id == tn_owner_cred.id for cred in owner.credentials)
+
+    user = await manager.async_create_user("test-user")
+    tn_user_cred = await provider.async_get_or_create_credentials({
+        'user': user.id
+    })
+    assert tn_user_cred.id != tn_owner_cred.id
+    assert tn_user_cred.is_new is False
+    assert any(cred.id == tn_user_cred.id for cred in user.credentials)
+
+    with pytest.raises(tn_auth.InvalidUserError):
+        await provider.async_get_or_create_credentials({
+            'user': 'invalid-user'
+        })
+
+
+async def test_validate_access(provider):
+    """Test validate access from trusted networks."""
+    with pytest.raises(tn_auth.InvalidAuthError):
+        provider.async_validate_access('192.168.0.1')
+
+    provider.hass.http = Mock(trusted_networks=['192.168.0.1'])
+    provider.async_validate_access('192.168.0.1')
+
+    with pytest.raises(tn_auth.InvalidAuthError):
+        provider.async_validate_access('127.0.0.1')
+
+
+async def test_login_flow(manager, provider):
+    """Test login flow."""
+    owner = await manager.async_create_user("test-owner")
+    user = await manager.async_create_user("test-user")
+
+    # trusted network didn't loaded
+    flow = await provider.async_credential_flow({'ip_address': '127.0.0.1'})
+    step = await flow.async_step_init()
+    assert step['step_id'] == 'init'
+    assert step['errors']['base'] == 'invalid_auth'
+
+    provider.hass.http = Mock(trusted_networks=['192.168.0.1'])
+
+    # not from trusted network
+    flow = await provider.async_credential_flow({'ip_address': '127.0.0.1'})
+    step = await flow.async_step_init()
+    assert step['step_id'] == 'init'
+    assert step['errors']['base'] == 'invalid_auth'
+
+    # from trusted network, list users
+    flow = await provider.async_credential_flow({'ip_address': '192.168.0.1'})
+    step = await flow.async_step_init()
+    assert step['step_id'] == 'init'
+
+    schema = step['data_schema']
+    assert schema({'user': owner.id})
+    with pytest.raises(vol.Invalid):
+        assert schema({'user': 'invalid-user'})
+
+    # login with invalid user
+    step = await flow.async_step_init({'user': 'invalid-user'})
+    assert step['step_id'] == 'init'
+    assert step['errors']['base'] == 'invalid_auth'
+
+    # login with valid user
+    step = await flow.async_step_init({'user': user.id})
+    assert step['type'] == 'create_entry'
+    assert step['data']['user'] == user.id