Hi,
In order to point your sub-domain to a diffrent server, you need to edit the domain's db file under /var/named/
Edit the file and change the A record of the subdomain to point to the new IP. Like,
from
test IN A YourServerIP
www.test IN A YourServerIP
TO
test IN A NewIP
www.test IN A NewIP
assuming 'test' as your sub-domain. Make sure you restart bind when the changes are done. Restart bind using the command as: /etc/init.d/named restart
With the above settings your sub-domain will entirely work from the new server. If you wish to host the sub-domain from our server and emails from a different one, in that case we will have to create a new zone for the sub-domain. So please raise a ticket with the details like sub-domain name, the new IP and we will do the needful.
Regards,
Jason S.