1. watchNS/chuden.co.jp
%dnsq mx www.chuden.co.jp asia1.akam.net
15 www.chuden.co.jp: 76 bytes, 1+1+0+0 records, response, authoritative, noerror query: 15 www.chuden.co.jp answer: www.chuden.co.jp 600 CNAME www.chuden.co.jp.edgekey.net
watchA/www.chuden.co.jp.edgekey.net
%dnsq mx xxx.chuden.co.jp asia1.akam.net
15 xxx.chuden.co.jp: 90 bytes, 1+1+0+0 records, response, authoritative, noerror query: 15 xxx.chuden.co.jp answer: xxx.chuden.co.jp 600 MX 10 chuden-co-jp.mail.protection.outlook.com
2. wildcard MX を確認
%dnsq mx \*.chuden.co.jp asia1.akam.net
15 \052.chuden.co.jp: 88 bytes, 1+1+0+0 records, response, authoritative, noerror query: 15 \052.chuden.co.jp answer: \052.chuden.co.jp 600 MX 10 chuden-co-jp.mail.protection.outlook.com
%dnsq mx zzz.xxx.chuden.co.jp asia1.akam.net
15 zzz.xxx.chuden.co.jp: 94 bytes, 1+1+0+0 records, response, authoritative, noerror query: 15 zzz.xxx.chuden.co.jp answer: zzz.xxx.chuden.co.jp 600 MX 10 chuden-co-jp.mail.protection.outlook.com
%dnsq mx xxx.www.chuden.co.jp asia1.akam.net
15 xxx.www.chuden.co.jp: 111 bytes, 1+0+1+0 records, response, authoritative, nxdomain query: 15 xxx.www.chuden.co.jp authority: chuden.co.jp 600 SOA ns1-104.akam.net hostmaster.akamai.com 2013021499 10800 3600 604800 600
この返答で正しい。