MX choosing

[Phil Mayers]

On 22/07/11 14:01, Feng He wrote:
> On Fri, Jul 22, 2011 at 5:58 PM, Tony Finch<dot at dotat.at>  wrote:
>
>>
>>   The question of whether a sender should attempt retries using the
>>   different addresses of a multihomed host has been controversial. The
>>   main argument for using the multiple addresses is that it maximizes the
>>   probability of timely delivery, and indeed sometimes the probability of
>>   any delivery; the counter-argument is that it may result in unnecessary
>>   resource use.
>>
>
> In any case, the SMTP client SHOULD try at least two addresses.
>

Many do not.

It is safer to have >1 MX, than 1 MX with >1 A record.