The role of Xhost

Xhost is used to control the access rights of X server.
Usually when you log on from Hosta to HostB to run the application on HostB,
As an application, Hosta is a client, but as a graph,
is displayed on the hosta, it needs to use the Hosta Xserver, so Hosta is
Server. So before landing to HostB, you need to run Xhost + on Hosta
Enable other users to access the Hosta Xserver.
Xhost + is to enable all users to access Xserver.
Xhost + IP enables users on IP to access xserver.
Xhost + Nis:user@domain enables NIS user users in domain to access
Xhost + Inet:user@domain enables inet users in domain to access.