What is wildcard domain name resolution?

Wildcard domain name resolution refers to the use of wildcard * (asterisk) as a secondary domain name to achieve that all the secondary domain names point to the same IP address.

For example, your domain name is abc.cn:

Make a record for * .abc.cn subdomain name a pointing to 222.222.222.222. After the record takes effect, when a visitor enters "123.abc.cn", "123.123.abc.cn", or even "! Any character such as @ #. $ % $ .6543.ww.a.abc.cn can point to the IP address 222.222.222.222.

Note:
Tested
"."
"-" Middle horizontal bar
"/" Left Diagonal Bar
These three characters cannot be used in Pan resolution. The problem occurs when these three characters cannot exist in the first character of the secondary domain name.

For example:

-.Abc.cn or -5.abc.cn

..Abc.cn or .5.abc.cn or .abc.cn

/.Abc.cn or/5.abc.cn

This cannot be parsed.