Upstream SSL IIS Performance

[d2radio]

Greetings,

I have an nginx server deployed infront of a Internet Information Services
6.0 server. The issue I have is that when requesting content from the IIS
server via HTTPS I am seeing an considerable increase in reponse time from
the upstream server. For example requesting the following javascript file I
am seeing the following log entires (Using a custom log format to catch
upsteam response times)

GET /client/javascript/libraries/query-string/2.1.7/query-min.js HTTP/1.1"
200 upstream 0.040 request 0.046 [for reversproxy via 172.25.50.203:80]

GET /client/javascript/libraries/query-string/2.1.7/query-min.js HTTP/1.1"
200 upstream 0.234 request 0.243 [for reverseproxy via 172.25.50.203:443]

As you can see it's taking up to an additional 200+ ms to serve up the js
file to nginx when talking to the upsteam server via HTTPS. I understand
that there is an overhead with HTTPS but I wouldn't expect it to be this
great. 

I also understand it would be better to serve the static content directly
from nginx but at the moment this isn't an option. 

I am currently running version 1.3.1 of nginx with the following configure
arguments

--with-http_ssl_module --add-module=/root/simpl-ngx_devel_kit-bc97eea
--add-module=/root/agentzh-headers-more-nginx-module-3580526
--add-module=/root/yaoweibin-ngx_http_substitutions_filter_module-f4080ae

I'm assuming all nginx ssl directives are for communication between the
client and nginx, Do I have any options for improving the https response
performance with the upsteam IIS server? Apart from talking to it via HTTP?

Thanks In Advance

Dan

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,229909,229909#msg-229909