named(네임서버)에서 별칭(CNAME)이 내부에서는 잘 되는데 외부?

fedora core2로 버젼없을 하고 나서부터 named(네임서버)에서 별칭(CNAME)이 먹히질 않습니다.
즉, cau.hs.kr ==> (별칭) www.cau.hs.kr
서버안에서는 nslookup을 하면 별칭이 뜨는데, 외부에서는 먹히질 않습니다. 어떻게 해야하는지 고수님들 부탁드립니다.

내부에서 nslookup www.cau.hs.kr을 했을경우....

Server: 210.104.1.3
Address: 210.104.1.3#53

www.cau.hs.kr canonical name = ns1.cau.hs.kr.
Name: ns1.cau.hs.kr
Address: 211.250.183.114

외부에서 nslookup www.cau.hs.kr을 했을경우....

Server: kns.kornet.net
Address: 168.126.63.1

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to kns.kornet.net timed-out

named 설정파일

##########################################
###### named.conf #################
##########################################

// generated by named-bootconf.pl

options {
directory "/var/named";
/*
* If there is a firewall between you and nameservers you want
* to talk to, you might need to uncomment the query-source
* directive below. Previous versions of BIND always asked
* questions using port 53, but BIND 8.1 uses an unprivileged
* port by default.
*/
// query-source address * port 53;
};

//
// a caching only nameserver config
//
controls {
inet 127.0.0.1 allow { localhost; } keys { rndckey; };
};
zone "." IN {
type hint;
file "named.ca";
};

zone "localhost" IN {
type master;
file "localhost.zone";
allow-update { none; };
};

zone "0.0.127.in-addr.arpa" IN {
type master;
file "named.local";
allow-update { none; };
};

zone "183.250.211.in-addr.arpa" IN {
type master;
file "named.rev";
allow-update { none; };
};

zone "cau.hs.kr" IN {
type master;
file "named.zone";
allow-update { none; };
};

include "/etc/rndc.key";

##########################################
###### named.rev #################
##########################################

@ IN SOA ns1.cau.hs.kr. root.ns1.cau.hs.kr. (
2003101118; Serial
28800; Refresh
14400; Retry
3600000; Expire
86400); Minimum

IN NS ns1.cau.hs.kr.
IN NS ns2.cau.hs.kr.

114 IN PTR ns1

##########################################
###### named.zone #################
##########################################

@ IN SOA ns1.cau.hs.kr. root.ns1.cau.hs.kr. (
2003101118; Serial
28800; Refresh
14400; Retry
3600000; Expire
86400); Minimum

IN NS ns1.csu.hs.kr.
IN NS ns2.cau.hs.kr.

@ IN A 211.250.183.114
IN MX 10 cau.hs.kr.

ns1 IN A 211.250.183.114

www IN CNAME ns1
; www IN CNAME @ 이렇게해도 안됩니다.