Websites with same domain name, different IP addresses?

[cbj4074]

I apologize if this question has been raised before; I did perform a search (and it returned 12 pages, with no relevant results in the first four).

I am wondering about the logic behind preventing two websites from having the same domain name -- when the IP addresses on which to listen are different.

I'm sure someone is thinking, "Why would you ever want to do that?"

I want to do it because I am migrating a website from one IP address to another IP address -- on the same server/ISPConfig installation.

Ideally, I would create identical websites -- one on each IP address -- so that once I update the DNS record (hosted externally), it doesn't matter which IP address the site-visitor hits when he visits the domain in question. The user experience should be the same for each IP address.

Is there a technical reason for which Apache cannot accommodate this setup?

Wouldn't it be perfectly valid to do something like this in the Apache configuration?

<VirtualHost 1.2.3.4>
DocumentRoot /www/example
ServerName www.example.com
</VirtualHost>

<VirtualHost 4.5.6.7>
DocumentRoot /www/example
ServerName www.example.com
</VirtualHost>

If I try that locally, Apache does not throw warnings/errors, and pages continue to be served from localhost without issue.

Thanks for any insights.