How can I move user accounts to a new server?

[jkl]

I failed to find that in the FAQ:

For obvious reasons I don’t have all passwords of the users on my e-mail server. I assume that I will have to upgrade the hardware in the next few years. Would it be enough to scp the passwords file so existing users will be kept on the new system?

[jggimi]

You'll need to transfer 4 files for userids: /etc/passwd, /etc/master.passwd, /etc/pwd.db, and /etc/spw.db for userids, and you'll need to transfer /etc/group for groups.

[jkl]

Thank you.