Is it possible to get all the domain names assigned to an IP address?
No, not generally. The DNS system was not designed for this kind of one-to-many search, just many-to-one. It may be specifically possible if you know all the domains are hosted by a single DNS provider, and even then it may not be doable.
To add to what sysadmin1138 has said, there are really only two possible ways to do this.
- Do a forward lookup on every possible domain name, including all possible subdomains if that is relevant to you.
- Do a reverse lookup on the IP address.
Number 1 is clearly impossible due to the number of lookups needed, plus much of the data would probably be invalid before you get even a few percent into the list.
Number 2 may work in some cases but in general not every forward lookup has a corresponding reverse lookup, which means you cannot get the complete list.