Mail2Web is a long running trustworthy mail access service. You simply enter your email address and password and their systems will fetch your email for you. While their main use is to allow roaming users tap their POP3/IMAP boxes via the web, their system is also handy during migrations.
Mail2Web provides and advanced settings area. In this area you can enter an IP address. This is very handy for migrations. To check your old server you simply:
- Goto http://www.mail2web.com/
- Click on the Advanced Login Link
- In the “Server name or IP address” field, enter the old server’s IP.
- Enter your user name and password
- Select IMAP as the protocol
- Click “Check Mail”
Your done! You should not be seeing the email on the old server.
Most migration tools take a backup of the information and then transfer it over to another server. During this time new email may arrive at the old server. If the backup has already been taken, this email will not be on the new server. Also, email may continue to go to the old server until DNS updates. Many ISPs cache DNS information and ignore TTL values. So while you may have lowered your TTL, emails may still go to the old server.
Using Mail2Web, you can let your clients easily check the old server for email without having to walk them through changing settings in their email clients. Once their DNS updates, they will be on the new server and checking email.
Some client’s DNS may lag behind in changing. You can use the steps above but with the new server’s IP to check email directly on the new server.
There are other tricks you can do like using a secondary mail server, redirecting the email, spooling email and/or resynchronizing email post-migration. All of these approaches work but they are time consuming. The Mail2Web trick works well, and I’ve found it sufficient for many of our clients.