Domain Name Using Underscore. An interesting character was the underscore. The same type of issues would apply however this isnt even an option - underscores cant be used in domains anyway as the character is not permitted.
Underscores are not allowed in domain names but are allowed in subfolders. For situations where renaming is not possible you can use private certificates and in some cases you can use a wildcard certificate that secures the entire domain. The DNS itself places only one restriction on the particular labels that can be used to identify resource records.
Hyphens are allowed in domain names themselves as well as subdomains and subfolders.
The underscore _ was recommended to be avoided in domain names because it could be easily confused with a hyphen - - RFC3467. Technically underscore is not a DNS character and while Windows will let you use an underscore when naming your machine it warns you that doing so may cause problems. For situations where renaming is not possible you can use private certificates and in some cases you can use a wildcard certificate that secures the entire domain. Avoid the use of underscores _ in domain names.