Recover an Exchange Server with Client Access Server role
Server Name: FW.1ask2.com and IP address:191.121.6.4/17
Exchange 2010 SP1 is installed in the default location. So, I don't use /TargetDir switch in SETUP /M:RecoverServer.
FW.1ask2.com is a node of Network Load Balancing.
dsmod computer "CN=FW,CN=Computers,DC=1ask2,DC=COM" -reset
Don't delete the computer account!!!!
Install Windows 2008 R2 with SP1 and name it as FW and Join it to 1ask2.com domain
Install Exchange Server 2010 SP1 with Client Access Server role and Management Console with command:
Setup /m:RecoverServer /InstallWindowsComponents
Windows PowerShell
import-module servermanager
Add-WindowsFeature nlb
Network Load Balancing Manager at FW cannot connect the node:Ex2.1ask2.com (Access denied)
Network Load Balancing Manager at EX2 can connect to both nodes:EX2 and FW.
Why?
Solution:
Run Network Load Balancing Manager with Administrator Privileges.
Best solution:
Control Panel--User Acounts-Credential Manager
Remove the entry for EX2.1ask2.com
Experiement
I delete the FW computer account from Active Directory.
Setup /M:RecoverServer failed.
You cannot install Exchange 2010 through the normal procedure, either.
To use the same name:FW and install Exchange 2010 on it, I have to clean up the Active Directory as:

After deleting the record CN=FW, I could install Exchange 2010 onto FW server.
Because it is freshly installed, we have to reconfigure it.
Enable-OutlookAnywhere –server FW –ExternalHostName ‘mail.1ask2.com’ –DefaultAuthenticationMethod ‘ntlm’ -SSLOffloading:$false
Set-EcpVirtualDirectory -ID "FW\EWS (Default Web Site)" -InternalUrl https://exserver.1ask2.com/ecp -ExternalURL https://mail.1ask2.com/ecp
Set-WebServicesVirtualDirectory -ID "FW\EWS (Default Web Site)" -InternalUrl https://exserver.1ask2.com/EWS/Exchange.asmx -ExternalURL:https://mail.1ask2.com/EWS/EXchange.asmx
Set-OabVirtualDirectory -ID "FW\OAB (Default Web Site)" -InternalUrl "https://exserver.1ask2.com/oab" -ExternalURL https://mail.1ask2.com/oab
Export Exchange Certificate from EX2 and Import and assign it onto FW