Setup for multiple domains on same VPS


We have 20 domains into a VPS and have two IPs allocated.

How do we go with setting up DNS for each domain?

1) We already have one wordpress installed on . We can assign fixed IP to this domain from our VPS

2) Regarding other 19 domains, do I have to create A record on their domain mgt. and link it back to the fixed IP of the domain?

3) How do we do domain mapping after?

Please note all the 19 domains share same IP and has differnt fixed IP.