Back in his original email on the topic, John quoted RFC 5321. However, 5321 also says, in section 7.9, that "... an SMTP server may refuse to accept mail for any operational or technical reason that makes sense to the site providing the server.", and then "When mail is rejected for these or other policy reasons, a 550 code SHOULD be used in response to EHLO (or HELO), MAIL, or RCPT as appropriate."
So I'm also +1 on keeping the policy intact for the reasons cited by Glen, and updating the 550 message sent by Postfix. This is conformant to the RFC.
Cheers,
Andy
On Mon, Dec 16, 2019 at 11:32 AM Phillip Hallam-Baker <phill@xxxxxxxxxxxxxxx> wrote:
On Mon, Dec 16, 2019 at 11:18 AM Nick Hilliard <nick@xxxxxxxxxx> wrote:Glen wrote on 16/12/2019 16:11:
> /^[0-9.]+$/ 550 RFC2821 violation
> /^\[[0-9.]+\]$/ 550 RFC2821 violation
>
> In just seconds, I can easily change the messages, or remove the
> rules, either with complete ease.
s/RFC2821 violation/policy violation/
+ let's move on.+1Try as we may, a 40 year old protocol that was designed before we had any of the technology required to mitigate abuse is not going to meet every modern need.What concerns me is not that the old protocols are failing but that the new protocols that are being deployed are closed. Sure, the Signal spec is open. But it is a closed system. You cannot connect to the Signal world from the outside.Millions of people are using non-SMTP and non-XMPP messaging systems every day. Perhaps deployment isn't quite as impossible as some people imagine.
