Xmanager Knowledge Base

XDMCP access control using TCP Wrapper

Last modified: Thursday, September 29, 2011 7:21 PM


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.


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: *