Rename our AD domain with Exchange online (curnetley hybrid mode) due to dot in netbios name?

Elliott Veares (Personal) 1 Reputation point
2021-04-02T21:48:01.903+00:00

Hi, where I work, we have a dot in our netbios name and is now causing us issues.

Our domain name dates back from the days of Windows NT 3.5 and unfortunately has a dot/period in the netbios name what has persisted since the domain was first set up back in the mid 90's.

This is now unfortunately causing us significant issues of being unable to use the Network Policy Server role in Windows Server 2016 to do RADIUS authentication for Business Wi-Fi as the network policy server is treating the dot in out netbios name as a FQDN, and subsequently fails to authenticate with a "No domain controller available" 4402 error.

I have already tried the "HKLM\SYSTEM\CurrentControlSet\Services\RasMan\PPP\ControlProtocols\Builtin" registry tweak without success.

From further research, this is expected behaviour and is because of a change in how the NPS role starting from server 2008 R2 was changed to allow domain lookups across domain boundaries.

Further more, we are at the end of Exchange 2010/2016 to Exchange online cloud migration. We are currently still running in Exchange Hybrid mode. Our Exchange 2010 boxes are very soon to be decommissioned, with just the single Exchange 2016 VM to be left behind what I guess will still be needed for local on-premise servers that need to send automated emails via basic SMTP.

I would say we have about 300-350 users in Exchange online. We also have some XP and 2000 clients on our domain still to, not many but a few none the less that run old but important software that is not officially compatible/supported with modern OS's. Additionally we also have 4 2016 Hyper-V clusters, any many servers. Both Physical and VM's.

What is the best, easiest and simplest way to remove the dot in our netbios name so that the NPS server role will work/be able to successfully authenticate against our DC's rather than try and fail in the process to use the dotted netbios name to do DNS lookups.

I know the process of renaming a AD domain name is simple when Exchange is not involved, but is complex and unsupported when Exchange is involved.

Regards: Elliott.

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  1. Andy David - MVP 142.3K Reputation points MVP
    2021-04-02T22:20:59.077+00:00

    If you remove all the Exchange Servers when done migrating, then install new ones as the "hybrid servers" once the domain is renamed, that would be supported.

    If you are syncing from on prem to 365 via AADConnect, then you need at least one Exch Server on prem for mgmt of course. ( to be supported)

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