multiple RRs of singleton type： DNS には CNAME で同じレコードを登録してはいけない。

-現象-

SUSE SLES11 内部イントラ用ＤＮＳサーバが動かない。ＹａＳＴで設定して、bind を再起動しても反映されない。 Bind never resolve intranet hosts on SUSE Linux. ゾーン全体が反応しない。 Hole of zone could not resolve.

service named restart をすると /var/log/messages に次のエラーが出る。

loading from master file master/my_zone failed: multiple RRs of singleton type


dns2:/etc # service named restart
Shutting down name server BIND - Warning: named not running! done
Starting name server BIND done <- No error
dns2:/etc # tail /var/log/messages
Aug 4 09:34:34 dns2 named[2541]: automatic empty zone: 8.B.D.0.1.0.0.2.IP6.ARPA
Aug 4 09:34:34 dns2 named[2541]: command channel listening on 127.0.0.1#953
Aug 4 09:34:34 dns2 named[2541]: the working directory is not writable
Aug 4 09:34:34 dns2 named[2541]: zone 0.0.127.in-addr.arpa/IN: loaded serial 42
Aug 4 09:34:34 dns2 named[2541]: zone 1.192.168.in-addr.arpa/IN: loaded serial 2012080400
Aug 4 09:34:34 dns2 named[2541]: dns_master_load: master/intra:23: ace-tree.intra: multiple RRs of singleton type
Aug 4 09:34:34 dns2 named[2541]: zone intra/IN: loading from master file master/intra failed: multiple RRs of singleton type
Aug 4 09:34:34 dns2 named[2541]: zone intra/IN: not loaded due to errors.
Aug 4 09:34:34 dns2 named[2541]: zone localhost/IN: loaded serial 42
Aug 4 09:34:34 dns2 named[2541]: running

-対策-

YaST のSOA レコードから CNAME の重複を削除した
Delete duplicated CNAME alias from master recorad. Works fine !

DNS Error: multiple RRs of singleton type

https://www.suse.com/ja-jp/support/kb/doc/?id=7009569

dns2:/var/lib/named # cat master/intra
$TTL 2d
@ IN SOA dns2.intra. root.dns2.intra. (

|
中略
|

ace-tree IN CNAME oes11x1
ace-tree IN CNAME oes11x2 Delete this line
grpwise IN CNAME gpw2012
email IN CNAME gpw2012　Delete this line
vpnx1 IN A 192.168.1.22
eilian IN A 192.168.1.21
zimbra IN A 192.168.1.23



dig コマンドで確認してみる。

corsair:~ # dig @dns2 ace-tree.intra

; <<>> DiG 9.6-ESV-R5-P1 <<>> @dns2 ace-tree.intra
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42492
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2

;; QUESTION SECTION:
;ace-tree.intra. IN A

;; ANSWER SECTION:
ace-tree.intra. 172800 IN CNAME oes11x1.intra.
oes11x1.intra. 172800 IN A 192.168.1.234　<-　正しく帰ってきたようだ ^_^ !

;; AUTHORITY SECTION:
intra. 172800 IN NS dns3.intra.
intra. 172800 IN NS dns2.intra.

;; ADDITIONAL SECTION:
dns2.intra. 172800 IN A 192.168.1.2
dns3.intra. 172800 IN A 192.168.1.3

;; Query time: 1 msec
;; SERVER: 192.168.1.2#53(192.168.1.2)
;; WHEN: Sat Aug 4 18:48:40 2012
;; MSG SIZE rcvd: 140

corsair:~ #


この症状は SUSE のみで出るのか他のディストリビューションで発生するかはわかりません。一般的な教科書には書いてないしなぁ。

-Keyword-

SUSE Bind YaST named DNS wouldn't work duplicated CNAME


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