Typically underscore is not used with Active Directory domain names as each AD corresponds to a DNS Domain as well and Internet DNS domains can not contain underscore. However, if the existing AD domain has an underscore - I understand there is no issue with Celerra CIFS server joining the AD Domain which has a underscore in the domain name. I remember one of my colleague tested it to work - but you may not get any official statement of support.

However, since you have already mentioned that Microsoft does not support domain with underscore - I wonder whether really you want a domain name with underscore.

Thanks,
Sandip

Hi

Thank you for your response. I understand your view. It is likely hard to be joined into domain with underscore without official support from EMC and Microsoft.

Thanks,