Nginx Works With Apache

I am doing my web like this:

1) nginx listening at port 80

2) apache listening at port 78

3) nginx throws all shtml pages to apache

they are working perfectly, except one small thing:

I don't want any public visitor may visit port 78 directly, for now, both:

[url]

[url]

are working for visitors.

Anybody knows how to block/hide port 78 to the public access?

my nginx config snippet:

Code:
location = /index.shtml {
proxy_pass [url]

}

my apache2 config snippet:

Code:
Listen 78
If I make apache as follows:

Code:
Listen 127.0.0.1:78
I will get 502 bad gateway when I visit:

[url]