ACL for cachemgr not working

I am using Squid 1.NOVM.18 on a RedHat 4.1 Linux [kernel 2.0.34] machine. I
have specified in squid.conf that only 'smarthost' can run the cachemgr.cgi
and no one else can. But, the fact is that, you can run it from anywhere.
My squid.conf relevant entries look like this:

---
acl manager proto cache_object
acl smarthost src 132.1.0.1/255.255.0.0
acl all src 0.0.0.0/0.0.0.0
 
acl SSL_ports port 443 563
acl Dangerous_ports port 7 9 19
acl CONNECT method CONNECT
 
http_access deny manager !smarthost
http_access deny CONNECT !SSL_ports
http_access deny Dangerous_ports
 
http_access allow  all
---
Now I can still access the cache manager from any host and from any IP. How
can I make it only be accessible from smarthost whose IP is 132.1.0.1?
Azfar