Classic email setup:

   [IMAP/POP3 >]  ---------> [EMAIL-CLIENT]

Is there any server application (open source) that would permit to store emails and act like a rely/proxy between the client and the mail server ?

  [IMAP/POP3 >]   --------->   [< IMAP/POP3 >]  ---------> [EMAIL-CLIENT]
    [Storage]                    [Storage]          

The purpose here is to keep emails data in a private location out of the main server and access it with a mobile/desktop clients (the email data would be kept at the "PROXY-RELY-SERVER" location only, client would connect to it, SMTP function is not needed). I found piler but i don't know yet if it could work like that.

Otherwise is there any email client that can act like an IMAP server for other clients to fetch emails from it? Or a simple IMAP server that can fetch other mailbox?

  • Do you expect to keep two different storages (but synced), both accessible from different clients ? Or everything is capted by the 'proxy-rely-server' (as you named it) serving all clients ?
    – user4089
    Apr 21, 2020 at 14:21
  • Is the 'proxy-rely-server' the common client
    – user4089
    Apr 21, 2020 at 14:40
  • @user4089 i updated the question, everything would be captured by the "proxy-rely-server" serving all the clients; that proxy server is not the final client app.
    – intika
    Apr 21, 2020 at 17:43
  • If that proxy server is not the final client box, I edited my answer suggesting ISPConfig.
    – user4089
    Apr 23, 2020 at 10:20

1 Answer 1


I assume everything is captured by the 'proxy-rely-server' (as you named it) serving all clients (the easy way) and it's the common client.

You probably need a couple of MRA and MDA installed on your 'proxy-rely-server'. The MDA will act as POP/IMAP server (for local use + other clients). The MRA (some kind of special MUA) will fetch emails from the 'real-mail-server' and store them on the MDA.

You have the choice between a lot of systems to achieve this. I just can suggest that, for now, I'm using Dovecot as MDA and Getmail as MRA.

The drawback is that all emails should be erased on the 'real-mail-server' as no syncing is -easily- possible. That means you'll have to take care of backups...

[edit following you comment]

As the 'proxy-rely-server' is NOT the common client, but some kind of server box (I guess), and as I'm a lazy guy, I can suggest you having a look at ISPConfig witch will do everything you need and a lot more. It's stable (based on debian or many other distros), very well documented, easy to install, easy to use, and very easy to maintain.


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