CentOS 7.x migrate CentOS 6.x postfix, dovecot, squirrelmail server

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CentOS 7.x migrate CentOS 6.x postfix, dovecot, squirrelmail server

Following steps can be used for migrating a running mail server setup from CentOS 6.8 created using Configuring basic SMTP, IMAP, POP and HTTP access for complete email on a single server to CentOS 7.4:

1. Create a new VM with necessary resources (Eg t2.micro)
2. Add elastic IP to instance if not done already
3. yum -y install vim
4. Mount partition to /home as desired
5. Copy keys from old server to new server as authorized
6. Add /etc/hosts entry in old server for pointing to new server with name (eg newserver)
7. yum -y install httpd mod_ssl
8. systemctl stop firewalld
9. TODO - Copy firewalld configuration from old server to new server
10. Edit /etc/httpd/conf.d/ssl.conf with

    SSLCertificateFile /etc/httpd/conf/ssl.crt
    SSLCertificateKeyFile /etc/httpd/conf/ssl.key
    SSLCACertificateFile /etc/httpd/conf/ca-bundle.pem

    and copy corresponding files from old server to new server

11. systemctl start httpd
12. systemctl status httpd
13. systemctl enable httpd
14. Copy home ( rsync -aHz --delete /home/ root@newserver:/home/ )
15. Repeat rsync again after it finishes for a second sync
16. cat /etc/passwd on old server. Copy all lines for UID >=500 and append corresponding lines to /etc/passwd on new server. The number of lines should match ls -1 /home | grep -v lost | wc -l Be watchful for IDs <500 which might appear in between (eg nscd)
17. Copy /etc/shadow lines of corresponding users from old server to new server
18. Copy /etc/group lines of corresponding users from old server to new server
19. Do "ls -l /home" on new server and all user and group names should appear properly
20. copy custom aliases from /etc/aliases to new server and update root alias appropriately
21. newaliases
22. yum -y install logwatch
23. yum -y install postfix
24. Edit /etc/postfix/main.cf on new server and correct values of following variables by looking at old server
    • myhostname
    • mydomain
    • myorigin
    • inet_interfaces
    • mydestination
    • home_mailbox
25. Set hostname in /etc/hostname file on new server
26. Use "hostname <fqdn>" command to set current hostname on new server
27. systemctl enable postfix
28. Add hostname against 127.0.0.1 in /etc/hosts
29. systemctl start postfix
30. systemctl status postfix
31. yum -y install dovecot
32. Edit etc/dovecot/conf.d/10-mail.conf and set

    mail_location = maildir:~/mail
    first_valid_uid = 500

    same as old server

33. systemctl enable dovecot
34. systemctl start dovecot
35. systemctl status dovecot
36. Refer Postfix_SMTP_authentication_using_dovecot and if authentication is enabled on old server then enable it appropriately on new server also
37. yum -y install wget
38. yum -y install epel-release
39. yum -y install squirrelmail
40. Disable selinux (setenforce 0, edit /etc/sysconfig/selinux and set SELINUX=disabled)
41. cd /usr/share/squirrelmail/config; ./conf.pl
    • Set Organization Preferences -> Organization name
    • Set Server Settings -> Domain
    • Set Server Settings -> IMAP Settings. Use values mail.sbarjatiya.com, 993, Secure (IMAP): true, Server software: dovecot
    • Setup mail sending using sendmail and not through SMTP
42. rsync /var/www/html from old server to new server
43. systemctl restart httpd
44. Add /etc/hosts entry for new server in laptop and try to open the new server with name and IP.
45. On old server stop httpd, dovecot and postfix
46. Again sync /home ( rsync -aHz --delete /home/ root@newserver:/home/ )
47. Change DNS entries to point to new server. If organization has local private DNS, then perhaps that may also require changes.
48. Check updated entries via public DNS servers after waiting for a minute or two
49. Copy /root/.ssh/authorized_keys from old server to new server
50. Comment /etc/host entry in laptop after DNS entry has been changed
51. Apply security group settings from old server to new server (HTTP, HTTPS, POP3, POP3S, SMTP, SMTPS, IMAP, IMAPS, SSH, Ping)
52. Do TLS_configuration_for_postfix if configured on previous server
53. Send test email from gmail to server and wait for receiving email on new server
54. Send test email from new server to gmail and wait for receiving email on Gmail account
55. stop and possibly terminate old server after few days. Elastic IP of old server can be released immediately after stopping.
56. If elastic IP is locked make a request for release
57. Fill AWS reverse entry form for email servers
58. CentOS 7.x Configure change password plugin for squirrelmail using poppassd

Refer: - https://serverfault.com/questions/291667/dovecot-getting-error-mail-access-for-users-with-uid-222-not-permitted

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