On last weekend my team was able to migration a full SharePoint Portal Server 2003 implementation (15 GB DB Size) to Microsoft Office SharePoint Server 2007. The major challenge in that project was that all the portal was 100% Customized with 22 Site Definitions, 20+ Webparts and 100% reconditioned UI. We have to work hard really which we at the end did and are successful. But today I want to share a thought here about Security Migration.
After the migration of the portal I accessed the portal Users and Groups page from Site actions tab. The old groups that are migration from the portal are given custom ; where an=1 naming convention which means that I have go and manfully update the users groups according to Microsoft Office SharePoint server user and groups which seems interesting to me. As SharePoint 2007 groups names are changed but still the migrated groups and not given the same name.
Another issue that we faced is adding a user with full control will not give the users full rights on the server. We have to manually move the user to new SharePoint 2007 group that it will have all the permissions on the portal.
Looking forward for some guidance.