X server may be configured to allow """any""" connection from
specified host. `xhost` is the utility allowing to control what hosts
are allowed to connect.

Basic synopsis is

||`xhost -`||enables host authentication protocol: only authenticated hosts may connect.||
||`xhost +`||disables any security protocols: any host may connect||
||`xhost +host`||adds specified host to the allowed hosts list||
||`xhost -host`||removes host from the allowed hosts list||

`host` may contain `inet:hostname` to allow clients from `hostname` to connect, `local` to allow connection from local clients and other, less used now, forms.

For the full information about xhost read `xhost(1x)` manual page and `Xsecurity(7x)` manual pages.

It is highly insecure to use host-based authentication protocols
in the non-controlled networks, so you
should probably consider using other authentication protocol, such as
[wiki:MIT-MAGIC-COOKIE-1], or even SshTunneling. But in
some cases, such as virtual machines inside one hardware machine,
host-based authentication is ok.

Example configuration using host-based authentication is the following:
`host1` runs `x2x` and wants to control display on `host2`.

On the host2:
{{{
host2% echo $DISPLAY
:0.0
host2% xhost +inet:host1 (or just 'xhost +host1')
host2%
}}}

On the host1:
{{{
host1% x2x -to host2:0
}}}