diff --git a/django/contrib/admin/views/doc.py b/django/contrib/admin/views/doc.py
index e060e53867..fa7088d5d9 100644
--- a/django/contrib/admin/views/doc.py
+++ b/django/contrib/admin/views/doc.py
@@ -5,7 +5,7 @@ from django.contrib.admin.views.decorators import staff_member_required
 from django.db import models
 from django.shortcuts import render_to_response
 from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist
-from django.http import Http404
+from django.http import Http404, get_host
 from django.core import urlresolvers
 from django.contrib.admin import utils
 from django.contrib.sites.models import Site
@@ -24,7 +24,7 @@ def bookmarklets(request):
     # Hack! This couples this view to the URL it lives at.
     admin_root = request.path[:-len('doc/bookmarklets/')]
     return render_to_response('admin_doc/bookmarklets', {
-        'admin_url': "%s://%s%s" % (os.environ.get('HTTPS') == 'on' and 'https' or 'http', request.META['HTTP_HOST'], admin_root),
+        'admin_url': "%s://%s%s" % (os.environ.get('HTTPS') == 'on' and 'https' or 'http', get_host(request), admin_root),
     }, context_instance=RequestContext(request))
 bookmarklets = staff_member_required(bookmarklets)
 
diff --git a/django/http/__init__.py b/django/http/__init__.py
index 34cd0a3005..75e1873a4c 100644
--- a/django/http/__init__.py
+++ b/django/http/__init__.py
@@ -252,3 +252,10 @@ class HttpResponseServerError(HttpResponse):
     def __init__(self, *args, **kwargs):
         HttpResponse.__init__(self, *args, **kwargs)
         self.status_code = 500
+
+def get_host(request):
+    """Gets the HTTP host from the environment or request headers."""
+    host = request.META.get('HTTP_X_FORWARDED_HOST', '')
+    if not host:
+        host = request.META.get('HTTP_HOST', '')
+    return host
diff --git a/django/middleware/common.py b/django/middleware/common.py
index 720de3c681..c34160cf1d 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -30,7 +30,8 @@ class CommonMiddleware:
                     return http.HttpResponseForbidden('<h1>Forbidden</h1>')
 
         # Check for a redirect based on settings.APPEND_SLASH and settings.PREPEND_WWW
-        old_url = [request.META.get('HTTP_HOST', ''), request.path]
+        host = http.get_host(request)
+        old_url = [host, request.path]
         new_url = old_url[:]
         if settings.PREPEND_WWW and old_url[0] and not old_url[0].startswith('www.'):
             new_url[0] = 'www.' + old_url[0]
@@ -56,7 +57,7 @@ class CommonMiddleware:
             if settings.SEND_BROKEN_LINK_EMAILS:
                 # If the referrer was from an internal link or a non-search-engine site,
                 # send a note to the managers.
-                domain = request.META['HTTP_HOST']
+                domain = http.get_host(request)
                 referer = request.META.get('HTTP_REFERER', None)
                 is_internal = referer and (domain in referer)
                 path = request.get_full_path()