I have also just noticed that mx1.tnz.mail.yahoo.com and
mx2.tnz.mail.yahoo.com have the same ip address (currently anyway).
Any sane reason why you'd want to do that?
dig xtra.co.nz mx
; <<>> DiG 9.2.5 <<>> xtra.co.nz mx
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28918
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;xtra.co.nz. IN MX
;; ANSWER SECTION:
xtra.co.nz. 157 IN MX 10 mx1.tnz.mail.yahoo.com.
xtra.co.nz. 157 IN MX 20 mx2.tnz.mail.yahoo.com.
;; AUTHORITY SECTION:
xtra.co.nz. 12331 IN NS alien.xtra.co.nz.
xtra.co.nz. 12331 IN NS terminator.xtra.co.nz.
;; ADDITIONAL SECTION:
mx1.tnz.mail.yahoo.com. 157 IN A 124.108.96.67
mx2.tnz.mail.yahoo.com. 1309 IN A 124.108.96.67
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Jean-Francois Pirus