INTRODUTION
Using TCP Wrapper to control XDMCP access is a not a commonly used access control method. This is because X Servers communicate with XDM (i.e. GDM / KDM / XDM) using UDP. So far, GDM is the only display manager that refers to TCP Wrapper to control host access.
However, if GDM is compiled without TCP Wrapper support, this feature may not be supported.
*This article requires remote server configuration. Administrator previlage may be required.
INFORMATION
To control XDMCP access of GDM by using TCP Wrapper, configure /etc/hosts.allow and /etc/hosts.deny.
For example, to allow a host, '.example.domain', enter the following line in/etc/hosts.allow:
gdm: .example.domain
To deny '.example.domain', enter the following line in /etc/hosts.deny:
gdm: .example.domain
To allow or deny all hosts from using GDM service, enter the following in the corresponding file:
gdm: *