diff --git a/seahub/auth/middleware.py b/seahub/auth/middleware.py
index ebf7f92829..8b27486e6d 100644
--- a/seahub/auth/middleware.py
+++ b/seahub/auth/middleware.py
@@ -1,7 +1,8 @@
 # Copyright (c) 2012-2016 Seafile Ltd.
-from django.contrib import auth
+from seahub import auth
 from django.core.exceptions import ImproperlyConfigured
 
+from django.conf import settings
 
 class LazyUser(object):
     def __get__(self, request, obj_type=None):
@@ -30,15 +31,15 @@ class RemoteUserMiddleware(object):
     If authentication is successful, the user is automatically logged in to
     persist the user in the session.
 
-    The header used is configurable and defaults to ``REMOTE_USER``.  Subclass
-    this class and change the ``header`` attribute if you need to use a
-    different header.
+    The header used is configurable and defaults to ``REMOTE_USER``. Set the
+    ``PROXY_AUTH_HEADER`` environment variable if you need to use a different
+    header.
     """
 
     # Name of request header to grab username from.  This will be the key as
     # used in the request.META dictionary, i.e. the normalization of headers to
     # all uppercase and the addition of "HTTP_" prefix apply.
-    header = "REMOTE_USER"
+    header = getattr(settings, 'PROXY_AUTH_HEADER', "HTTP_REMOTE_USER")
 
     def process_request(self, request):
         # AuthenticationMiddleware is required so that request.user exists.
diff --git a/seahub/base/accounts.py b/seahub/base/accounts.py
index ee965a43a0..6a3e769525 100644
--- a/seahub/base/accounts.py
+++ b/seahub/base/accounts.py
@@ -576,6 +576,50 @@ class AuthBackend(object):
         if user.check_password(password):
             return user
 
+class ProxyRemoteUserBackend(AuthBackend):
+    """
+    This backend is to be used in conjunction with the ``RemoteUserMiddleware``
+    found in the middleware module of this package, and is used when the server
+    is handling authentication outside of Django.
+    By default, the ``authenticate`` method creates ``User`` objects for
+    usernames that don't already exist in the database.  Subclasses can disable
+    this behavior by setting the ``create_unknown_user`` attribute to
+    ``False``.
+    """
+    # Create a User object if not already in the database?
+    create_unknown_user = True
+
+    trust_proxy = getattr(settings, 'TRUST_PROXY_AUTHTENTICATION', False)
+
+    def authenticate(self, remote_user):
+        """
+        The username passed as ``remote_user`` is considered trusted.  This
+        method simply returns the ``User`` object with the given username,
+        creating a new ``User`` object if ``create_unknown_user`` is ``True``.
+        Returns None if ``create_unknown_user`` is ``False`` and a ``User``
+        object with the given username is not found in the database.
+        """
+        # End the remote user auth process if the proxy is not trusted
+        if not remote_user or not self.trust_proxy:
+            return
+        user = None
+        username = self.clean_username(remote_user)
+
+        # Note that this could be accomplished in one try-except clause, but
+        # instead we use get_or_create when creating unknown users since it has
+        # built-in safeguards for multiple threads.
+
+        user = self.get_user(username)
+        return user
+
+    def clean_username(self, username):
+        """
+        Performs any cleaning on the "username" prior to using it to get or
+        create the user object.  Returns the cleaned username.
+        By default, returns the username unchanged.
+        """
+        return username
+
 ########## Register related
 class RegistrationBackend(object):
     """
diff --git a/seahub/settings.py b/seahub/settings.py
index a9ee7c8e60..d76a54c9cc 100644
--- a/seahub/settings.py
+++ b/seahub/settings.py
@@ -116,6 +116,7 @@ MIDDLEWARE_CLASSES = (
     'django.middleware.csrf.CsrfViewMiddleware',
     'django.contrib.messages.middleware.MessageMiddleware',
     'seahub.auth.middleware.AuthenticationMiddleware',
+    'seahub.auth.middleware.RemoteUserMiddleware',
     'seahub.base.middleware.BaseMiddleware',
     'seahub.base.middleware.InfobarMiddleware',
     'seahub.password_session.middleware.CheckPasswordHash',
@@ -271,6 +272,7 @@ CONSTANCE_DATABASE_CACHE_BACKEND = 'default'
 AUTHENTICATION_BACKENDS = (
     'seahub.social_core.backends.weixin_enterprise.WeixinWorkOAuth2',
 
+    'seahub.base.accounts.ProxyRemoteUserBackend',
     'seahub.base.accounts.AuthBackend',
     'seahub.oauth.backends.OauthRemoteUserBackend',
 )