We are having a strange problem and I was interested if anyone has any thoughts.
We have the following configuration for the "argylediamonds.com.au" domain we manage:
argylediamonds.com.au. MX IN 1200 mail.riotinto.com. [Preference = 20]
argylediamonds.com.au. MX IN 1200 mail.argylediamonds.com.au. [Preference = 50]
argylediamonds.com.au. MX IN 1200 mail.riotinto.com.au. [Preference = 10]
argylediamonds.com.au. NS IN 3599 dns.argylediamonds.com.au.
argylediamonds.com.au. NS IN 3599 ns1.rescuegroup.com.
mail.argylediamonds.com.au. A IN 1200 203.166.51.147
ns1.rescuegroup.com. A IN 129816 203.103.84.232
Effectively, mail to this domain should go via "mail.riotinto.com.au" then "mail.riotinto.com" and as a last resort ""mail.argylediamonds.com.au".
What we are seeing is that messages (about 10-20 a day) arrive at "mail.argylediamonds.com.au" without ever having attempted to use the "mail.riotinto.com.au" and "mail.riotinto.com" servers. This has been confirmed by comparing logs and noting that there have been no refused connections.
So, it appears to be a DNS issue but I'm stuffed if I can see why this is happening. Any thoughts?
