[clug] Single MX, multiple A records

Alex Osborne aosborne at nla.gov.au
Fri Aug 1 02:07:42 GMT 2008

Michael James wrote:
> What is the standard behaviour
>  when a DNS name returns multiple A records?
According to this guy, it varies from implementation to implementation.


 From what I've seen, DNS servers will usually return multiple A records 
in a random order each time they're queried.  So likely even if the 
client host always just picks the first one, if the first delivery 
attempt happens to hit the dud server, the second or third attempt will 
hit the working server.  So I guess normally (unless you're particularly 
unlucky) the mail will just have a chance of being delayed a while.


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