The data has been imported from another ISPConfig server to the new ISPConfig server database. Then I found that ISPConfig has recreated the accounts and entries in the following files automatically:
- /etc/passwd, /etc/shadow and /etc/group
I would to confirm whether this is true!!!
But the problem is that /etc/shadow does not contain the passwd.
The solution is to copy exactly the /etc/passwd, /etc/group and /etc/shadow from the old server to the new one. This solves the problem. No config problem with dovecot only a few adjustments is needed as follows:
protocols = imap imaps pop3 pop3s
listen = *
mail_location = maildir:~/Maildir
pop3_uidl_format = %08Xu%08Xv
You may tune the config as you wish
invoke-rc.d dovecot restart
then do a netstat -tanlp to view whether pop3 pop3s imap and imaps port and program are running