At present, how many mainstream intranet penetration methods have you used?

Sometimes, when we want to access the data of the host at home or the company, either because the host is under the intranet, or because it is a public network IP randomly assigned by the operator, it is very difficult to connect to the host directly to obtain information. So, is there any way to solve this problem? The answer is intranet penetration. When in the intranet