Custom 403 page not working(?) in combination with "deny all"

[Peter Vandenberk]

(apologies if this is a re-post, but the GMANE auto-authorizer 
seems to have gobbled my original post)

Hi all,

I am trying to configure nginx 0.6.32 to serve a customized 
403.html error page, but it doesn't appear to be working...  
I am using "nginx -t" to check my config files, so I don't think 
it's a configuration issue.

No matter how I try to shift things around in the config file, 
nginx never seems to serve my custom 403.html page, but 
instead always returns the built-in, hardcoded "403 Forbidden" 
page (the one with the HR, and nginx version footer).

I have verified that the 403.html can be served by nginx (so I'm 
pretty sure it's not a path or permissions issue), and have also 
tried to find relevant postings on the net... the closest match I 
could find to my problem is:

http://osdir.com/ml/web.nginx.english/2007-01/msg00046.html

... but I don't have an upstream backend in this particular nginx 
configuration, so I don't think the re-writing response from Igor 
applies to my problem.

Any ideas/pointers that may be of help?  I have included all relevant 
information I can think of at the bottom of this email

Many thanks in advance,

Peter

PS - I have also compiled my nginx instance with --with-debug 
and am using the debug_connection directive to try to understand 
what's going on, but I must admit the log output is so verbose that 
I'm struggling to get my head around it, even for a single HTTP 
request ... is there something specific I should be looking for?  
or would it help if I post the entire debug output?

VERSION INFO

pvdb at jupiler ~ $ /usr/local/nginx/sbin/nginx -V
nginx version: nginx/0.6.32
built by gcc 4.1.1 20070105 (Red Hat 4.1.1-51)
configure arguments: --with-http_dav_module --with-debug
pvdb at jupiler ~ $ _

NGINX CONFIG (http section)

http {

    allow  192.168.1.0/24;  
    allow  127.0.0.1;     
    deny all;              

    ...

}

NGINX CONFIG (server section)

server {

        ...

        error_page  403              /403.html;
        location = /403.html {
            root   /usr/share/nginx/html;
        }

        ...
}

FYI: I have tried various combinations/variants/locations 
for the above snippets, but nothing seems to actually 
serve my custom 403.html page