问题
A client is moving from their old hosting to mine. They have a few email accounts on the old hosting and I want to move all the emails on the old hosting to mine. How can I do this? If I download them with POP can I then upload them to the new hosting?
回答1:
The answer depends on the mail server that you are using. Yes, you can download all the mail messages with POP3, but the upload to your mail server will depend on the type of mail server. I am not aware of any mail servers that provide a tool to import mail messages.
Most mail servers store the email message in a file, and you can certainly drop the files in the folder where they are stored, but that does not mean that it will be visible, you will have to deal with how the mail server index those files.
I suggest looking at the specifications for your mail server.
回答2:
If you access both accounts with IMAP (most hosts support this now) instead of POP, you can literally drag and drop the messages between folders/inboxes for the two email accounts.
Also, depending on the type of hosting they're moving from/to, you may be able to use a feature of your new server's control panel to do the importing...unless you're doing it manually on a vanilla VPS or dedicated. There are still options, but you'd need to confirm here how your new server is setup and what the old server looks like.
If you're only talking about a couple of accounts with a few folders each, you may just want to consider IMAP as your path of least resistance. The transfer will primarily depend on your own Internet connection, as most hosting companies have connections faster than yours.
Lastly, if both servers share a similar format for the mailbox, you might want to just rsync the email over to the new server (assuming you have root access on both servers) to the proper email directory. Depending on the email box format, you may be able to simply run a server command to "convert" the mailbox to the format your server is expecting.
来源：https://stackoverflow.com/questions/5953227/transfer-emails-to-new-hosting