Am 20.10.20 um 12:15 schrieb R. Diez:
First of all, thanks for your answer.
What is the problem with having huge online mailboxes? Just choose a >
good european provider that has encryption all the way through to
their> storage platform.
We already have a European ISP with a standard e-mail server. I wanted
to keep our own mail server on premises, so that it is not exposed on
the Internet. The current server fetches (and removes) all e-mails from
the ISP. That has many advantages, for example, internal e-mail still
works in case of an Internet outage.
If I wanted to change the setup, I would have to start evaluating such
an "encryption all the way through to their storage platform" feature. I
am not sure that it is worth the effort. In any case, that sounds like a
limiting factor when choosing another ISP, in case the current one
starts making trouble.
I had exactly the same idea about migrating. You have to think twice >
about moving emails around of users. They do not like it ;)
> [...]
I don't really want to do that, that's why I wrote "If I set a mailbox
size limit, users will have to delete old mails by themselves".
I do not know much about the legal aspects, but in case we need to keep
all e-mails for legal data retention requirements, I would like to store
those e-mails separately, so that if a user deletes it, the original
e-mail is still archived somewhere else.
That is why I mentioned the Postfix's BCC feature. The idea is that you
have a separate mailbox where a separate copy of all e-mails to and from
all users land. That is the separate mailbox where I wanted to
reorganise e-mails by date, in order to archive the e-mails in smaller
chunks on a yearly basis. Those e-mails do not need to be online after
all. Chances are, they will never be needed anyway.
I have created an 'archive' environment on a distributed filesystem,
and it
takes me quite a lot of persuading to have people (or allow me) to move
messages from common Sent and Inbox mailboxes to the Archive namespace
> [...]
I am actually a newbie in mail service matters, but my guess is that
there is no amount of persuasion that could possibly help. You have to
set a hard limit per mailbox and let the users deal with it, don't you?
Otherwise, sooner or later the server will overload. Or I would need to
become a full-time e-mail server admin, which is not an option either!
I am actually a friend of having 2 backup disks that rotate, where one
is always physically off premises, and offline. But I wonder how I could
keep the backups encrypted and synchronised with 2 rotating disks. Maybe
Veracrypt + rsync.
I am hoping that the amount of big attachments in all incoming and
outgoing mail still fits in normal external USB 3.0 disks. Or at least a
few years' worth of it per disk. But I still would not want to have say
1 TB of mail data online. That would make the VM unmanageable for
part-time sysadmins like me.
[@~]# mailbox-ls.sh testtest size
> [...]
I would not trust anyone else's programming with my
users email, you should also not.
I am not sure that I would trust my own e-mail server programming
abilities either. 8-)
If you have written such scripts, perhaps you could point me to some
example scripts that I could use as a starting point for such e-mail
reorganisation tasks?
> [...]
But when I migrate to mdbox this is not necessary anymore.
I am not sure that I would trust a file format where the indexes cannot
be rebuilt if they become corrupt. If I need an advanced format for
search performance reasons, I would probably consider an SQL-based
backend then.
I do not like the sound of "Postfix BCC feature", I use sendmail and I
can duplicate messages with that, without altering anything in them.
> [...]
I am actually not sure yet how to achieve the copying. I am still a
little confused anyway. 8-)
On the incoming side, I may not use Postfix at all, because Dovecot
actually needs to download the e-mails from the ISP mail server. I am
hoping that I can use a single "catch all" mailbox on the ISP. So I
would need to copy the incoming e-mails in another way.
On the outgoing side, anything sent (actually per SMTP relay) through
our internal mail server could be copied somehow with some BCC feature.
But if the user connects to the external ISP's SMTP servers directly,
then I cannot get a copy so easily. Maybe I need to force the users to
always use the internal mail server for sending.
In any case, let's say that the duplicate mails, stored somewhere else
for data retention purposes, get altered in some way, like some header
is added or changed in a predictable way. I am thinking of a header like
"BCC: dataretent...@example.com". Why would that be a problem?
Best regards,
rdiez
why not use archive solution
like
https://blog.sys4.de/mailarchiv-mit-dovecot-und-postfix-sortiert-nach-datum-mailadressen-und-ein-ausgehend-unterordnern-de.html
sort with sieve, its not exact what you search but should be enough to
go on, you might consider a double fetch with i.e getmail
https://blog.sys4.de/abholdienst-fur-mail-de.html
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