Here are two procedures I used when switching over mail servers. You
may have to adjust a bit, but it's a good start. The first one was
migrating from GoDaddy to our own server. The second was migrating one
qmail server to another in the same company (hardware/OS/QMail upgrade).
DNS Preparations
One week before migration - change TTL in the DNS records to 60
Ensure both new and old mail servers have A record entries. Example:
; 04/29/06 Added new A and MX records for e-mail migration
mail1 IN A xxx.xxx.xxx.xxx
IN MX 10 mail1.example.com.
Reload named on all DNS servers
Verify DNS is working by looking at logs and executing
nslookup/dig/host. Example:
[EMAIL PROTECTED] root]# tail -1000 /var/log/messages | grep "named\["
Apr 29 18:03:23 server named[16530]: loading configuration from
'/etc/named.conf'
Apr 29 18:03:23 server named[16530]: no IPv6 interfaces found
Apr 29 18:03:23 server named[16530]: zone example.com/IN: loaded serial
2006042901
[EMAIL PROTECTED] root]# nslookup mail1.example.com
Server: xxx.xxx.xxx.xxx
Address: xxx.xxx.xxx.xxx#53
Non-authoritative answer:
Name: mail1.example.com
Address: xxx.xxx.xxx.xxx
[EMAIL PROTECTED] root]#
Set up e-mail accounts on new server using same credentials as the
accounts on the old server.
Friday Night
Change the MX records to turn off the old mail servers. Reload named on
all DNS servers.
; 04/29/06 Removed old mail servers
; IN MX 50 mailstore1.secureserver.net.
; IN MX 60 smtp.secureserver.net.
; 04/29/06 Added new A and MX records for e-mail migration
mail1 IN A xxx.xxx.xxx.xxx
IN MX 10 mail1.example.com.
; email IN CNAME email.secureserver.net.
[EMAIL PROTECTED] root]# service named reload
Reloading named: [ OK ]
[EMAIL PROTECTED] root]# tail -1000 /var/log/messages | grep "named\["
Apr 29 18:09:21 server named[16530]: loading configuration from
'/etc/named.conf'
Apr 29 18:09:21 server named[16530]: no IPv6 interfaces found
Apr 29 18:09:21 server named[16530]: zone example.com/IN: loaded serial
2006042902
[EMAIL PROTECTED] root]#
Verify DNS is working by executing nslookup/dig/host. Example:
[EMAIL PROTECTED] root]# dig -t mx example.com
; <<>> DiG 9.2.3 <<>> -t mx example.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31889
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 4
;; QUESTION SECTION:
;example.com. IN MX
;; ANSWER SECTION:
example.com. 60 IN MX 10 mail1.example.com.
;; AUTHORITY SECTION:
example.com. 60 IN NS ns1.example.com.
example.com. 60 IN NS ns1.example.com.
example.com. 60 IN NS ns2.example.com.
;; ADDITIONAL SECTION:
mail1.example.com. 60 IN A xxx.xxx.xxx.xxx
ns1.example.com. 60 IN A xxx.xxx.xxx.xxx
ns2.example.com. 60 IN A xxx.xxx.xxx.xxx
ns1.example.com. 60 IN A xxx.xxx.xxx.xxx
;; Query time: 12 msec
;; SERVER: xxx.xxx.xxx.xxx#53(xxx.xxx.xxx.xxx)
;; WHEN: Sat Apr 29 18:15:43 2006
;; MSG SIZE rcvd: 178
[EMAIL PROTECTED] root]#
Send an e-mail from an account on the new server to the domain being
migrated and check for delivery to the correct mail server. View mail
on server using web interface.
[EMAIL PROTECTED] root]# echo "test of new mail server" | mail -s "test 1"
[EMAIL PROTECTED]
[EMAIL PROTECTED] root]#
Command
tail -100f /var/log/qmail/current | tai64nlocal | grep delivery
Output
2006-04-29 18:19:59.374196500 starting delivery 1038: msg 10422667 to
remote [EMAIL PROTECTED]
2006-04-29 18:19:59.911565500 delivery 1038: success:
xxx.xxx.xxx.xxx_accepted_message./Remote_host_said:_250_OK_id=1Fa0bP-00022U-Mz/
View new mail in webmail.
Monday Morning
Check all mail and retrieve mail from the old servers. Then change mail
server settings in the mail clients to the new mail server. Get mail again.
Decommission the old mail server.
Restore DNS TTL to 3600 seconds.
Another procedure I used (2 weeks ago) was much simpler (QMail to QMT):
1 week before migration:
Set DNS TTL to 1800.
Create same accounts on new server.
NOTE: Ensure quotas are similar and spam protection is same.
Day of migration (Saturday):
Change DNS A and MX records to new IP address.
Sunday:
Copy old squirrelmail settings to new server.
Copy old mail to new system.
Tuesday:
Copy over any remaining non-spam mail to new system.
1 week later:
Decommission old server.
Change TTL to 3600.
Notes:
Spammers will continue hitting the old server DAYS later, even with a 30
min TTL on the A and MX records. Since most of the spam coming in is
coming from residential users, I must conclude that Windows XP does not
honor DNS TTL settings. Anyone care to comment?
George Toft, CISSP, MSIS
623-203-1760
Naveen wrote:
Dear list,
Presently my company using ALT N MDaemon , and we would like to change
our mail server to Qmail Toaster.
I already installed Qmail with QMT-ISO.
Can some one suggest me that the best way to change over to qmail from
Mdaemon with out down time or may be less down time.
Regads,
Naveen
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