diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 97bd2bf97f2592d03932606e83bbfbc829aafdfc..0c6973f9b67a080eadc206e6322b4ae63ae82198 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Allow default url options to accept host with protocol such as `http://`
+
+        config.action_mailer.default_url_options = { host: "http://mydomain.com" }
+
+    *Richard Schneeman*
+
 *   Ensure that digest authentication responds with a 401 status when a basic
     header is received.
 
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 97ac462411c8fbbb42ea05bdaba494359b5f7321..ab5399c8eaa9e25cc1f9eb23b3d18604a5b16527 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -59,8 +59,9 @@ def build_host_url(options)
           result = ""
 
           unless options[:only_path]
+            protocol = extract_protocol(options)
             unless options[:protocol] == false
-              result << (options[:protocol] || "http")
+              result << protocol
               result << ":" unless result.match(%r{:|//})
             end
             result << "//" unless result.match("//")
@@ -83,6 +84,16 @@ def rewrite_authentication(options)
           end
         end
 
+        # Extracts protocol http:// or https:// from options[:host]
+        # needs to be called whether the :protocol is being used or not
+        def extract_protocol(options)
+          if options[:host] && match = options[:host].match(/(^.*:\/\/)(.*)/)
+            options[:protocol] ||= match[1]
+            options[:host]     =   match[2]
+          end
+          options[:protocol] || "http"
+        end
+
         def host_or_subdomain_and_domain(options)
           return options[:host] if !named_host?(options[:host]) || (options[:subdomain].nil? && options[:domain].nil?)
 
diff --git a/actionpack/test/dispatch/url_generation_test.rb b/actionpack/test/dispatch/url_generation_test.rb
index e56e8ddc579c5c69aa116cd625b0d92548d55980..41235290921cab16e0544f92bcdb37a212b5b6ee 100644
--- a/actionpack/test/dispatch/url_generation_test.rb
+++ b/actionpack/test/dispatch/url_generation_test.rb
@@ -48,6 +48,14 @@ def app
       https!
       assert_equal "http://www.example.com/foo", foo_url(:protocol => "http")
     end
+
+    test "extracting protocol from host when protocol not present" do
+      assert_equal "httpz://www.example.com/foo", foo_url(host: "httpz://www.example.com", protocol: nil)
+    end
+
+    test "formatting host when protocol is present" do
+      assert_equal "http://www.example.com/foo", foo_url(host: "httpz://www.example.com", protocol: "http://")
+    end
   end
 end