redhat企业5配置DNS服务器问题

我配置好了DNS服务器之后本机可以解析域名，但是其他同网段的机器能ping通IP却ping不通设置的域名，请高人给条路走。
以下是我的配置：
1、hosts文件

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6
172.16.0.6 www.skyclasss.com www
172.16.0.6 mail.skyclasss.com mail
172.16.0.6 ftp.skyclasss.com ftp
================================================

2、named.caching-nameserver.conf

//
// named.caching-nameserver.conf
//
// Provided by Red Hat caching-nameserver package to configure the
// ISC BIND named(8) DNS server as a caching only nameserver
// (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
// DO NOT EDIT THIS FILE - use system-config-bind or an editor
// to create named.conf - edits to this file will be lost on
// caching-nameserver package upgrade.
//
options {
listen-on port 53 { 172.16.0.6; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
query-source port 53;
query-source-v6 port 53;
allow-query { any; };
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
view localhost_resolver {
match-clients { localhost; };
match-destinations { localhost; };
recursion yes;
include "/etc/named.rfc1912.zones";
};

=================================================

3、named.rfc1912.zones

// named.rfc1912.zones:
//
// Provided by Red Hat caching-nameserver package
//
// ISC BIND named zone configuration for zones recommended by
// RFC 1912 section 4.1 : localhost TLDs and address zones
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
zone "." IN {
type hint;
file "named.ca";
};

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

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 "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {
type master;
file "named.ip6.local";
allow-update { none; };
};

zone "255.in-addr.arpa" IN {
type master;
file "named.broadcast";
allow-update { none; };
};

zone "0.in-addr.arpa" IN {
type master;
file "named.zero";
allow-update { none; };
};

zone "skyclasss.com" IN {
type master;
file "skyclass.zone";
allow-update { none; };
};

zone "0.16.172.in-addr.arpa" IN {
type master;
file "172.16.0.zone";
allow-update { none; };
};

=============================================

4、skyclass.zone

$TTL 86400
skyclasss.com. IN SOA skyclasss.com. root.skyclass.com. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum

skyclasss.com. IN NS www.skyclasss.com.
www IN A 172.16.0.6
mail IN A 172.16.0.6
ftp IN A 172.16.0.6

============================================================

5、172.16.0.zone

$TTL 86400
@ IN SOA skyclasss.com. root.skyclasss.com. (
1997022700 ; Serial
28800 ; Refresh
14400 ; Retry
3600000 ; Expire
86400 ) ; Minimum
IN NS www.skyclasss.com.
6 IN PTR www.skyclasss.com.
6 IN PTR mail.skyclasss.com.
6 IN PTR ftp.skyclasss.com.

============================================================

麻烦各位帮忙看看！