Redhat Enterprise 5: DNS server configuration problems

Redhat Enterprise 5: DNS server configuration-general Linux technology-Linux technology and application information. For details, refer to the following section. After the DNS server is configured, the local machine can resolve the domain name, but other machines in the same network segment can ping the IP address, but the domain name cannot be pinged.
My configurations are as follows:
1. hosts file

# Do not remove the following line, or various programs
# That require network functionality will fail.
127.0.0.1localhost.localdomainlocalhost
: 1localhost6. localdomain6localhost6
172.16.0.6www.skyclasss.comwww
172.16.0.6mail.skyclasss.commail
172.16.0.6ftp.skyclasss.comftp
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2. named. caching-nameserver.conf

//
// Named. caching-nameserver.conf
//
// Provided by Red Hat caching-nameserver package to configure
// 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 ";
};

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3. named. rfc1912.zones

// Named. rfc1912.zones:
//
// Provided by Red Hat caching-nameserver package
//
// Isc bind named zone configuration for zones recommended
// 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 "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.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 ;};
};

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4. skyclass. zone

$ TTL86400
Skyclasss.com. IN SOAskyclasss.com. root.skyclass.com .(
42; serial (d. adams)
3 H; refresh
15 M; retry
1 W; expiry
1D); minimum

Skyclasss.com. IN NSwww.skyclasss.com.
Www IN A172.16.0.6
Mail IN A172.16.0.6
Ftp IN A172.16.0.6

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5. 172.16.0.zone

$ TTL86400
@ 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.

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Please take a look!