If you need to host multiple servers using circular DNS (or other load balancing methods), this is a good idea. This will allow you to use a single host name and, as a rule, not cause crawling and indexing problems on the search engine side (since crawlers do not see multiple URLs for content).
If you need to host a host or domain names (for any reason), it is better to choose one preferred version and make sure that only it is indexed. To do this, you can use rel = canonical link elements on alternate versions. In general, however, I would recommend working to prevent the appearance of several host / domain names that are visible to the user and search engines, since the technical problems of hosting (mirror hosts) are hidden from view (as mentioned in the first part).
If you need to use several ccTLDs for hosting in country-specific domains, I highly recommend that you make sure that you actually have specific content on each site (and not just mirroring one version). More on this - http://googlewebmastercentral.blogspot.com/2010/03/working-with-multi-regional-websites.html