A .ac domain name can be used and registered by anyone. Companies located on Ascension Island, as well as companies or corporations that have business-relations with that Island mainly use this domain name.
No special requirements. Anyone can register a .ac domain name.
No special requirements.
All letters (a-z) and numbers (0-9) are allowed; hyphens (-) are also allowed, however not at the beginning or at the end of the domain name. A domain name should be between 3 and 63 characters long.