Alex van den Bogaerdt wrote:
I would argue that 'EHLO
mailserver.domain.com' is more useful than 'EHLO [192.168.1.1]' even
though the former is incorrect, and the latter correct (according to RFC
5321) with dynamic IP/NAT.
IMHO 192.168.1.1 is not an internet IP address. And that is a
I'm sorry, but that can't be the case.
Otherwise, how does Thunderbird send mail to a local mail server on a
private network? It can't, because it hasn't got an Internet host name,
or an Internet IP address, so can't issue a valid EHLO command.
Similarly, how does ANY SMTP client behind a NAT router with dynamic IP
(ie pretty much any home user) send a message anywhere? If what you say
is the case, then that is cutting off half the world from the SMTP network!
As far as I can see RFC 5321 doesn't say it has to be a routable IP
address to be used in an address literal.
As far as I am aware, RFC 4409 doesn't relax the requirements of RFC
2821/5321 for the EHLO parameter, so 'use message submission' is not the
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