diff --git a/lib/thin/connection.rb b/lib/thin/connection.rb
index ec105b8e..d1c78e4b 100644
--- a/lib/thin/connection.rb
+++ b/lib/thin/connection.rb
@@ -72,6 +72,10 @@ def pre_process
       if @backend.ssl?
         @request.env["rack.url_scheme"] = "https"
 
+        if @backend.respond_to?(:port)
+          @request.env['SERVER_PORT'] = @backend.port.to_s
+        end
+
         if cert = get_peer_cert
           @request.env['rack.peer_cert'] = cert
         end
diff --git a/spec/connection_spec.rb b/spec/connection_spec.rb
index c9aede35..6cc4b6f2 100644
--- a/spec/connection_spec.rb
+++ b/spec/connection_spec.rb
@@ -78,7 +78,7 @@
     expect(@connection.remote_address).to eq("127.0.0.1")
   end
   
-  it "should return nil on error retreiving remote_address" do
+  it "should return nil on error retrieving remote_address" do
     allow(@connection).to receive(:get_peername).and_raise(RuntimeError)
     expect(@connection.remote_address).to be_nil
   end
@@ -143,4 +143,12 @@
   it "should not set as threaded when app do not respond to deferred?" do
     expect(@connection).not_to be_threaded
   end
+
+  it "should have correct SERVER_PORT when using ssl" do
+    @connection.backend = double("backend", :ssl? => true, :port => 443)
+
+    @connection.process
+
+    expect(@connection.request.env["SERVER_PORT"]).to eq("443")
+  end
 end