Change to Internal Domino Host Name

We currently have an external domain name of xyz.co.uk and the domino environment was set up with these details however we have now moved all of our servers over to a new internal domain of 123.xyz.co.uk due to internal access issues of our websites etc. The problem I have is how do I move the domino servers over to the new internal domain of 123.xyz.co.uk ? we are still using the xyz.co.uk as our external domain name and our external email addresses are still xyz.co.uk but I am having so many problems with sso on any new domino servers that I create as they are all set up as 123.xyz.co.uk so the sso documents won’t work. At the moment I have managed to make some changes using a global domain document but I really need to move the domino servers over to the new internal domain name.

Any help would be most appriciated as I can’t seem to be able to get this one sorted and it is now affecting our new portal / domino integration project. I am sure that this is something really simple but I just can’t see it and any changes I seem to make don’t have any effect.

Subject: Change to Internal Domino Host Name

Has anyone got any ideas on this as i’m still having the issue.