Virtualboxを使用してDNSサーバーとWebサーバーをセットアップしました。 DNSサーバーのIPアドレスは192.168.56.101で、Webサーバーは192.168.56.102です。
DNSサーバーの構成ファイルは次のとおりです。
named.conf:
[quan@localhost ~]$ Sudo cat /etc/named.conf
//
// named.conf
//
// Provided by Red Hat bind 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.
//
options {
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 address * port 53;
//forward first;
forwarders { 8.8.8.8; 8.8.4.4; };
listen-on port 53 { 127.0.0.1; 192.168.56.0/24; };
allow-query { localhost; 192.168.56.0/24; };
recursion yes;
dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
};
logging {
channel default_debug {
file "data/named.run";
severity debug 10;
print-category yes;
print-time yes;
print-severity yes;
};
};
zone "quantran.com" in {
type master;
file "named.quantran.com";
};
zone "56.168.192.in-addr.arpa" in {
type master;
file "named.192.168.56";
allow-update { none; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
named.quantran.com:
[quan@localhost ~]$ Sudo cat /var/named/named.quantran.com
$TTL 86400
quantran.com. IN SOA dns1.quantran.com. root.quantran.com. (
100 ; serial
3600 ; refresh
600 ; retry
604800 ; expire
86400 )
IN NS dns1.quantran.com.
dns1.quantran.com. IN A 192.168.56.101
www.quantran.com. IN A 192.168.56.102
名前付き.192.168.56:
[quan@localhost ~]$ Sudo cat /var/named/named.192.168.56
$TTL 86400
$Origin 56.168.192.in-addr.arpa.
@ IN SOA dns1.quantran.com. root.quantran.com. (
100 ; serial
3600 ; refresh
600 ; retry
604800 ; expire
86400 ) ; minimum
IN NS dns1.quantran.com.
101.56.168.192.in-addr.arpa. IN PTR dns1.quantran.com.
102 IN PTR www.quantran.com.
ホストから通常のルックアップを試みると(ホストが使用するネームサーバーがDNSサーバー192.168.56.101のみになるように構成しました):
quan@quantran:~$ Host www.quantran.com
www.quantran.com has address 192.168.56.102
quan@quantran:~$ Host dns1.quantran.com
dns1.quantran.com has address 192.168.56.101
しかし、逆ルックアップを試みると:
quan@quantran:~$ Host -v 192.168.56.101 192.168.56.101
Trying "101.56.168.192.in-addr.arpa"
Using domain server:
Name: 192.168.56.101
Address: 192.168.56.101#53
Aliases:
Host 101.56.168.192.in-addr.arpa not found: 2(SERVFAIL)
Received 45 bytes from 192.168.56.101#53 in 0 ms
quan@quantran:~$ Host -v 192.168.56.102 192.168.56.101
Trying "102.56.168.192.in-addr.arpa"
Using domain server:
Name: 192.168.56.101
Address: 192.168.56.101#53
Aliases:
Host 102.56.168.192.in-addr.arpa not found: 2(SERVFAIL)
Received 45 bytes from 192.168.56.101#53 in 0 ms
では、なぜ逆ルックアップを実行できないのですか?ゾーン構成ファイルに何か問題がありますか?
前もって感謝します :)
ああ、逆ルックアップを実行したときのログファイル/var/named/data/named.runからの出力は次のとおりです。
quan@quantran:~$ Host 192.168.56.102 192.168.56.101
Using domain server:
Name: 192.168.56.101
Address: 192.168.56.101#53
Aliases:
Host 102.56.168.192.in-addr.arpa not found: 2(SERVFAIL)
/var/named/data/named.run:
02-Jun-2014 15:18:11.950 client: debug 3: client 192.168.56.1#51786: UDP request
02-Jun-2014 15:18:11.950 client: debug 5: client 192.168.56.1#51786: using view '_default'
02-Jun-2014 15:18:11.950 security: debug 3: client 192.168.56.1#51786: request is not signed
02-Jun-2014 15:18:11.950 security: debug 3: client 192.168.56.1#51786: recursion available
02-Jun-2014 15:18:11.950 client: debug 3: client 192.168.56.1#51786: query
02-Jun-2014 15:18:11.950 client: debug 10: client 192.168.56.1#51786: ns_client_attach: ref = 1
02-Jun-2014 15:18:11.950 query-errors: debug 1: client 192.168.56.1#51786: query failed (SERVFAIL) for 102.56.168.192.in-addr.arpa/IN/PTR at query.c:5428
02-Jun-2014 15:18:11.950 client: debug 3: client 192.168.56.1#51786: error
02-Jun-2014 15:18:11.950 client: debug 3: client 192.168.56.1#51786: send
02-Jun-2014 15:18:11.950 client: debug 3: client 192.168.56.1#51786: sendto
02-Jun-2014 15:18:11.951 client: debug 3: client 192.168.56.1#51786: senddone
02-Jun-2014 15:18:11.951 client: debug 3: client 192.168.56.1#51786: next
02-Jun-2014 15:18:11.951 client: debug 10: client 192.168.56.1#51786: ns_client_detach: ref = 0
02-Jun-2014 15:18:11.951 client: debug 3: client 192.168.56.1#51786: endrequest
02-Jun-2014 15:18:11.951 client: debug 3: client @0xb537e008: udprecv
また、named.confのログセクションにいくつかの変更を加えました。
ホストのresolv.conf:
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.56.101
#nameserver 127.0.1.1
問題は、実際にはファイルのアクセス許可設定です。/var/namedフォルダーの内容は次のとおりです。
[root@localhost quan]# ls -alZ /var/named/
drwxr-x---. root named system_u:object_r:named_zone_t:s0 .
drwxr-xr-x. root root system_u:object_r:var_t:s0 ..
drwxrwx---. named named system_u:object_r:named_cache_t:s0 data
drwxrwx---. named named system_u:object_r:named_cache_t:s0 dynamic
-rw-r-----. root root unconfined_u:object_r:named_zone_t:s0 named.192.168.56
-rw-r-----. root named system_u:object_r:named_conf_t:s0 named.ca
-rw-r-----. root named system_u:object_r:named_zone_t:s0 named.empty
-rw-r-----. root named system_u:object_r:named_zone_t:s0 named.localhost
-rw-r-----. root named system_u:object_r:named_zone_t:s0 named.loopback
-rw-r--r--. root root unconfined_u:object_r:named_zone_t:s0 named.quantran.com
drwxrwx---. named named system_u:object_r:named_cache_t:s0 slaves
ご覧のとおり、named.quantran.comというファイルはchmod 644であり、namedユーザーが読み取ることができます。ただし、named.192.168.56(逆引きゾーン構成ファイル)はchmod 640であり、namedユーザーが読み取ることはできません。したがって、逆ルックアップを正常に実行できませんでした。それでも、named.quantran.comがchmod 644 @@であったのに、なぜchmod640だったのか理解できません。