[SOLVED] Zimbra Primary Server incoming mail issue

[borngunners]

I have followed the following wiki: Split Domain - Zimbra :: Wiki to setup zimbra as the primary server. I have successfully migrated my account as a test with all the inbox. I can send out email from my account to anyone, but I can't receive incoming email. Instead, it is being sent to my old server instead of my zimbra server. My email domain in the zimbra server is borngunners@mail.example.com. And that is the same with my old server, which is borngunners@mail.example.com. The name of my zimbra server is zimbra.mail.example.com. The admin account on the zimbra server is admin@zimbra.mail.example.com, which is sending and receiving emails to and from any where in the world. from the wiki, I was told to do the following:
3. Change your MX record so mail from the internet flows into the Zimbra MTA first. (This is the last step! You will bounce mail if you make this change before configuring the entire system and testing that mail flow is working as desired.)

When you are ready to move a user from the old system to the new system just run this command (where zimbra.example.com is the name of your Zimbra server):

Now is this being done from my ISP or within the zimbra server itself? If within the zimbra server, how do I go about doing it?

*note* I am using a public ip and when i did a dig, my MX record is 100 zimbra.mail.example.com

My ISP domain is example.com

Remember the domain and names are not real, but fit the sample of my configuration.

thanks

I am trying to go live with my server now...

[phoenix]

If these two servers are on different public IP addresses then you need to modify your external DNS records to point to the new servers IP address. If they are on different LAN IP addresses then you need to modify your NAT router to forward mail (port 25) to the private IP of the new server.

[borngunners]

They are on different public IP addresses. What I want is for some users to still receive mails on the old server while I migrate other users to the new mail server, where everyone can still receive their emails.