Re: Rejecting messages based on recipient MTA''s IP address

[Allen Coates]

On 01/10/2020 08:01, Ansgar Wiechers wrote:
> On 2020-09-30 Allen Coates wrote:
>>
>> Does the SMTP daemon resolve a destination if there is no MX record?
> 
> Normally Postfix will check for an MX first, and if that is absent check
> for an A record for the domain. This is standard MTA behavior as defined
> in section 5 of RFC 5321.
> 
> <https://tools.ietf.org/html/rfc5321#section-5.1>

and then, presumably, the fall-back relay, if it is defined.

Thanks for clearing up my confusion.

Allen C