dovecot - Feb 2023 - Pigeonhole Sieve Vacation Reply-To peculiarity with inbound AWS-SES

> Am 07.02.2023 um 17:54 schrieb jeremy ardley <jeremy at ardley.org>:
> 
> On 7/2/23 22:01, Dr. Rolf Jansen wrote:
>> To begin with, usage of Amazons Simple Email Service (SES) is mandatory
for outgoing mails from AWS-EC2 instances.
> 
> I run AWS-EC2 instances using postfix to send a receive mail. They can send
direct assuming I set up suitable SPF, but they typically forward mail to
another host under my  control that is not on AWS to use as the outgoing server.
OK, that?s another use case. Many do use a full fledged Postfix/Dovecot
installation. However the outgoing port 25 into the internet is blocked by AWS,
and therefore we may either use a third party relay for our outgoing emails or
may use SES, which is not that bad - except some unusual peculiarities.

Of course, if I wanted to, I could change, this is something which is under my
control.

That would however change nothing with the other issue, of my Vacation plugin
responding with a nonsense MAIL TO address to third parties using SES, this is
not under our control. There is even no channel to argue about it.

Best regards

Rolf Jansen

On 8/2/23 05:08, Dr. Rolf Jansen wrote:
>> Am 07.02.2023 um 17:54 schrieb jeremy ardley<jeremy at
ardley.org>:
>>
>> On 7/2/23 22:01, Dr. Rolf Jansen wrote:
>>> To begin with, usage of Amazons Simple Email Service (SES) is
mandatory for outgoing mails from AWS-EC2 instances.
>> I run AWS-EC2 instances using postfix to send a receive mail. They can
send direct assuming I set up suitable SPF, but they typically forward mail to
another host under my  control that is not on AWS to use as the outgoing server.
> OK, that?s another use case. Many do use a full fledged Postfix/Dovecot
installation. However the outgoing port 25 into the internet is blocked by AWS,
and therefore we may either use a third party relay for our outgoing emails or
may use SES, which is not that bad - except some unusual peculiarities.
>
This is off topic, but to be precise:

- AWS throttles but does not block traffic to a *destination* port 25.
- The *origin* port on the EC2 instance is an unprivilged port, not port 25
- If you use a relayhost you typically send from an unprivilged EC2 port 
to port 587 on the relay host

Jeremy
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