Internal Domains Not Valid

[fdsg72-lux]

Hi there,

Background:
I completed the following How To's to setup fresh install of Ubuntu 8.10 with ISPConfig and RoundCube WebMail:

=> Ubuntu 8.10: http://www.howtoforge.com/perfect-server-ubuntu-8.10
=> ISPConfig post-install setup: http://www.howtoforge.com/ispconfig-2.x-first-steps-p3
=> RoundCube Webmail: http://www.howtoforge.com/roundcube_webmail_ispconfig

Issue:
I am not able to create domain names used for internal lab environments e.g. mydomain.internal, yourdomain.local, etc. When I try to create a new master domain called 'mydomain.internal' I get the error message "Invalid domain name: mydomain.internal" after hitting the save button. See screen captures for details

Help:
Please let me know where to update the logic that is validating domain names so that I can create these internal lab only domain names?

Thanks,
Faan

[till]

Try e.g.:

mydomain.int