Looking for a guide to collect all e-mail from the ISP mail server

[Marc Roos]

Maybe get something like Zimbra, such solutions also have support that 
you can buy when you need it or don't have time (I guess).



-----Original Message-----
From: R. Diez [mailto:rdiezmail-2006 at yahoo.de] 
Sent: Sunday, October 25, 2020 6:57 PM
To: dovecot at dovecot.org
Subject: Looking for a guide to collect all e-mail from the ISP mail 
server

Hi all:

I am evaluating mail server solutions for a small business. The trouble 
is, I am only a part-time admin and a newbie to mail servers.

Most guides I have seen are rather unrealistic: they encourage you to 
expose your e-mail server to the Internet, and hope that you have the 
resources 
to keep it patched up.

I would rather have an internal mail server that collects e-mails from a 
standard ISP mail server.  It is like the old "POP3 Connector" that came 
with 
Microsoft Exchange.  Sometimes, there is a mailbox per user on the ISP, 
and a corresponding one on the local server.  Other times, there is a 
single 
"catch all" or "multidrop" mailbox on the ISP.

Users can still access their internal mailboxes from outside through an 
OpenVPN connection.  The goal is that only VPN, and perhaps SSH, are 
accessible from the outside.  We do not need to arrange any special SMTP 
configuration with the ISP either.

This kind of mail server setup is rather different to the standard 
configuration. You do not normally need you own antivirus and spam 
filter, and you 
do not need to configure SSL certificates, MX or SPF DNS records. Most 
ISP handle that correctly and economically.  Internal e-mail does not 
leave 
your LAN, and your internal SMTP server is just a relay for the external 
ISP SMTP server.

Furthermore, most guides do not explain how to setup an autoresponder 
("I am on holiday until xxx") so that users can enable theirs with the 
mouse. 
Editing configuration files over SSH is not really an option for normal 
users. This detail is important because it could be the only thing I 
need 
above standard e-mail. Further groupware features can be seen as nice 
but ultimately unnecessary luxury, and a basic shared calendar can be 
accomplished with a separate server like https://radicale.org/ and a 
calendar client like one built into Thunderbird. Hopefully, that is all 
I would 
need for a small business.

Can anyone point me to the kind of guide I need? Failing that, I would 
need information or examples about using fetchmail, getmail or similar 
software 
with Dovecot.  Good or bad experiences from you guys would also help.

Each of those tools has a detailed man page, but there are many options 
and ways with different advantages and disadvantages.  I would need a 
simpler 
guide to get started.

I am aware that there are pre-packaged mail server solutions that would 
perhaps bring an easy-to-use autoresponder, but I haven't seen one yet 
that 
where you could tick a box like "this server is only internal and 
collects mail from the ISP server" during installation. Nor have I seen 
instructions 
about reconfiguring the mail server for my ISP mail scenario.

I am prepared to learn more and write my own Perl scripts and/or 
installation guide, but it would be stupid to waste time if something 
easy already 
exists.  After all, the setup I am describing (external ISP mail server 
+ internal mail server) is not so weird.

Thanks in advance,
   rdiez