Periods cannot be registered under domain name rules.
When you see periods in a URL it is referred to as a subdomain.
Subdomains are intended to be used to host different content than what is found in the main domain and as an alternative to having to register a bunch of individual domain names.
Can special characters be used in domain names?
No. Unfortunately you can’t use ampersands (&) as part of your domain name. Characters that you can use in your domain name include letters, numbers and hyphens.
Can I use hyphens in domain names?
Domain names are only allowed to use letters, numbers, and hyphens.
Which are not allowed in domain names?
ANSWER: Regardless of the extension, all domain names must follow the same character rules You can use letters (abc), numbers (123) and dashes/hyphens (—). Spaces are not allowed and the domain can’t begin or end with a dash.
Can I use an underscore in a domain name?
It is perfectly legal to have an underscore in a domain name. Let me quote the standard, RFC 2181, section 11, “Name syntax”: The DNS itself places only one restriction on the particular labels that can be used to identify resource records. Domains with underscores are very common in the wild.