I have one questions i am a reseller and i want to know is this possible i can assign 1 ip to my client for example one for my client website and one for this Emails. Like if my client emails not works but my client website should be up.
Yes, this can be achieved. But to do that you will need root access to the server. As a reseller your web host won't allow you to do so.
without root option we have option. in cpanel every time create a new account it will mail local mail server and remote mail server. you just choose remote mail server and given the address. that`s it