miktex get host by name failed in tcp_connect() solution

1. a problem of user rights (writing access forbidden for simple users). A solution can consist in installing not in C:\Program Files (or the (x86) companion), because then the UAC (user access control) will not be involved. A simple user can always install in his %UserProfile% (the problem could then be an institutional size limit).
2. a Firewall. Solution: deactivate firewall or better, when possible, set a temporary exception.
3. an Antivirus program. Solution again: deactivate program or better, when possible, set a temporary exception.
4. a temporary problem of the MiKTeX.org (at least one subdomain is called on every installation or update when “the nearest” repository, i.e. a random one, is selected, cf. Can I avoid connecting to MiKTeX update server?). Then you only could wait and try again after some time.

Turn off antivirus then turn off the firewall. Then upload the current version of “miktex” under the user. Don’t install it under Program Files.