DNS/KnotResolver/behavior/nxdomainについて、ここに記述してください。 $ dig qqqqqq.qmail.jp {{{ ; <<>> DiG 9.11.1 <<>> qqqqqq.qmail.jp ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 40350 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ; COOKIE: 6f4580205537f7c46d50d4785909e555e0d7a23cde60cfb3 (good) ;; QUESTION SECTION: ;qqqqqq.qmail.jp. IN A ;; AUTHORITY SECTION: qmail.jp. 2560 IN SOA a.ns.qmail.jp. hostmaster.m.qmail.jp. 1493567262 16384 2048 1048576 2560 ;; Query time: 12 msec ;; SERVER: 127.0.0.3#53(127.0.0.3) ;; WHEN: Wed May 03 23:12:37 JST 2017 ;; MSG SIZE rcvd: 126 }}} tmaeno@tm:~$ dig qqqqqq.qmail.jp {{{ ; <<>> DiG 9.11.1 <<>> qqqqqq.qmail.jp ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 58530 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ; COOKIE: e1d2e1338c513ada956c89b65909e56916cb3123628d7773 (good) ;; QUESTION SECTION: ;qqqqqq.qmail.jp. IN A ;; AUTHORITY SECTION: qmail.jp. 2540 IN SOA a.ns.qmail.jp. hostmaster.m.qmail.jp. 1493567262 16384 2048 1048576 2560 ;; Query time: 0 msec ;; SERVER: 127.0.0.3#53(127.0.0.3) ;; WHEN: Wed May 03 23:12:57 JST 2017 ;; MSG SIZE rcvd: 126 }}} {{{ @400000005909e55f04c66b74 [ 0][plan] plan 'qqqqqq.qmail.jp.' type 'A' @400000005909e55f04c6fbfc [29049][iter] 'qqqqqq.qmail.jp.' type 'A' id was assigned, parent id 0 @400000005909e55f04c80d6c [29049][resl] NT check; qqqqqqqmailjp cut qmailjp @400000005909e55f04c81154 [29049][resl] kr peekpkt qqqqqqqmailjp ret -2 @400000005909e55f04c8153c [15852][iter] 'qqqqqq.qmail.jp.' type 'A' id was assigned, parent id 0 @400000005909e55f04c81924 [15852][resl] => querying: '14.192.44.5' score: 11 zone cut: 'qmail.jp.' m12n: 'QQqQqq.QMail.jp.' type: 'A' proto: 'udp' @400000005909e55f057ef1bc [15852][iter] <= rcode: NXDOMAIN @400000005909e55f057fb124 [15852][ pc ] => answer cached for TTL=900 @400000005909e55f057fd064 [15852][resl] <= server: '14.192.44.5' rtt: 12 ms @400000005909e55f058041ac [ 0][resl] finished: 4, queries: 1, mempool: 32800 B @400000005909e5732526f2bc [ 0][plan] plan 'qqqqqq.qmail.jp.' type 'A' @400000005909e5732527872c [63459][iter] 'qqqqqq.qmail.jp.' type 'A' id was assigned, parent id 0 @400000005909e5732527aa54 [63459][ pc ] => satisfied from pktcache @400000005909e5732527aa54 [63459][iter] <= rcode: NXDOMAIN @400000005909e5732528e6bc [ 0][resl] finished: 4, queries: 1, mempool: 32800 B }}}