[pve-devel] [PATCH v4 many 00/11] notifications: add SMTP endpoint

[Lukas Wagner]

On 11/9/23 13:16, Dietmar Maurer wrote:
>> On 11/8/23 16:52, Dietmar Maurer wrote:
>>>> This patch series adds support for a new notification endpoint type,
>>>> smtp. As the name suggests, this new endpoint allows PVE to talk
>>>> to SMTP server directly, without using the system's MTA (postfix).
>>>
>>> Isn't this totally unreliable? What if the server responds with a
>>> temporary error code? (An MTA retries several times).
>>
>> The notification system has no mechanism yet for queuing/retries,
>> so yes, at the moment a SMTP endpoint would indeed be less reliable than
>> a 'sendmail' endpoint. I'm not sure though if I would call it
>> 'totally unreliable'.
> 
> This kind of notification system is quite popular for (PHP) web-sites contact
> form. I have seen many over-simplified implementation overs the years,
> and yes, it is totally unreliable.
> 
> That is why we always used an MTA to deliver mails...

I see. What would be your suggestion? To not have such a plugin at all?
I implemented this because it was explicitly mentioned by Thomas in the 
tracking bugzilla issue for an overhauled notification system [1].
Not having to configure Postfix if one wants to use an external
SMTP relay seems to be add quite a lot of value to the user (e.g. 
judging from [2] and [3])
As a compromise, maybe we could just add a note to the docs
that discusses the reliability aspects of 'sendmail' vs 'smtp'
endpoints?

[1] https://bugzilla.proxmox.com/show_bug.cgi?id=4156
[2] https://bugzilla.proxmox.com/show_bug.cgi?id=2965
[3] 
https://forum.proxmox.com/threads/get-postfix-to-send-notifications-email-externally.59940/

-- 
- Lukas