Hi Flavio,
At 19:53 01-09-2013, [email protected] wrote:
Going back to the topic, when it comes to SMTP (rfc5321) the existance
of PTR is not strictly required, but, as stated in 4.1.1, in absence of
reverse mapping the client should use an address literal in the
helo/ehlo phase instead of an fqdn.
My reading of the text is that if the client cannot determine its
domain name it can use the address literal instead. There are
various techniques which can be used to determine the domain
name. The absence of a PTR causes delays.
In terms of operations it's easier if there is a PTR.
Regards,
-sm
