Make a backup of:

/etc/group
/etc/passwd
/etc/shadow
/etc/apache2/vhosts/Vhosts_ispconfig.conf
/etc/postfix/local-host-names
/etc/postfix/virtusertable
/etc/proftpd*.conf

cd /var/lib/named/etc/bind

Backup BIND files if use DNS

named.conf
all the pri.* zone files

Create 3 sql dumps: ALL your MySQL databases

mysqldump -p --all-databases > all_databases.sql
mysqldump -p --databases mysql > mysql.sql
mysqldump -p --databases db_ispconfig > ispconfigdb.sql

“mysqldump” does not dump the INFORMATION_SCHEMA database. If you name that database explicitly on the command line, mysqldump silently ignores it.

remember that the mysql & test databases are specials! You need to remove them from the all_databases.sql dump, before import in the new server

To show the databases on your mysql server run

mysqlshow -p

Create a Postfix transport, so that all emails are forwarded to the new server, until the MX records of your domains have switched to the new server, run:

echo "*  smtp:[<FQDN or IP address, of new server>]" >> /etc/postfix/transport
postmap /etc/postfix/transport
postconf -e 'transport_maps = hash:/etc/postfix/transport'

Stop Postfix so that no new mails can arrive:

/etc/init.d/postfix stop

Backup /var/www on the old server

cd /var
tar -pczf www.tar.gz www/

Remember that -p stands for keep permissions

Install ISPConfig, it MUST BE THE SAME VERSION OF THAT ON THE OLD SERVER

Regarding the mysql database: have a look at the users & db tables in the all_databases.sql dump file, then add the user & db rowsthat don't exist on the new server but on the old server.

So, completely remove the mysql database from the all_databases.sql file, then create all the databases running:

mysql -u root -p < all_databases.sql
mysql -u root -p < mysql.sql

It is safe to replace the ISPConfig database with the old one

Log in to ISPConfig and go to

Management -> Server -> Settings

and change the IP address(es) there.

Copy local-host-names and virtusertable to /etc/postfix

Open local-host-names and replace the old hostname with the new one, add the hostname of the old server at the bottom so that the new server accepts the forwarded mails, then run

postmap /etc/postfix/virtusertable

Replace Vhosts_ispconfig.conf with the one from the old server. Open it and replace the old IP address with the new one, then restart apache

/etc/init.d/apache restart

Transfer www.tar.gz to /var and unpack it:

cd /var
mv www www_orig
tar xvfz www.tar.gz

Transfer proftp*.conf files, open them and replace the old IP address with the new one Restart proftpd

/etc/init.d/proftpd restart