How to control access for specific IP-addresses of clients when using as mail proxy

[mikiso]

Hi, 

I am running nginx 1.0.8 for mail proxy , and I would like to add access
control feature(by IP address) to this proxy. 
For HTTP, there is http access module for this purpose, however mail
module doesn't seem to have this feature.
Do someone know how to implement this feature?

I found ngx_tcpwrapper on https://launchpad.net/ngx-tcpwrappers ,
 but unfortunately this is also only for HTTP.



Thanks and Regards,
Soichiro

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,216892,216892#msg-216892