This article covers:
- all the information, that I managed to find out or figure out,
- all the bottlenecks I had to resolve and all the walls, I hit,
- some additional info or alternative methods,
about migrating all messages from some mail account to Gmail, using imapsync and IMAP protocol.
The imapsync is an extremely flexible and powerful tool, that also has an on-line counterpart (so you don’t get your hands too dirty), and its documentation simply surpasses imagination, so it is certainly able to transfer all the messages between virtually any IMAP servers, not just between Gmail.
But this article focuses on external IMAP server –> Gmail scenario. For other scenarios, you should find some tips here, but you may need to consult imapsync documentation and the Internet or to use another solution.