When you use the NET USER command, the /workstations: switch is limited to defining 8 workstation that a user can log on to.

When you use the DSADD USER or DSMOD USER Active Directory command-line tool, the ability to set the userWorkstations attribute is NOT included.

I have scripted userWorkstations.bat to allow you to set more that 8 workstations into a user's userWorkstations attribute.

The syntax for using userWorkstations.bat is:

userWorkstations UserDN LogonTo UWOK


UserDN   is the Distinguished Name of the user you wish to maintain.                              LogonTo  is a sting of NetBIOS computer names, separated by commas, that you wish to allow the user to logging on to.                              UWOK     is a call directed environment variable that will contain a                                       Y if the maintenance was successful, or an N if the maintenance failed.
NOTE: userWorkstations.bat use AdMod.exe, which must be located in a folder that is in your PATH.

NOTE: I don't know what the absolute maximum number of workstations that you can configure is, but I gave up testing after reaching a large number.

userWorkstations.bat contains:

@echo off                              if \{%3\}==\{\} @echo userWorkstations UserDN LogonTo UWOK&goto :EOF                              setlocal                              set UWOK=N                              set userDN=%1                              set LogonTo=%2                              set LogonTo=%LogonTo:"=%                              call :quiet>nul 2>&1                              endlocal&set %3=%UWOK%                              goto :EOF                              :quiet                              for /f "Tokens=*" %%a in ('admod -b %userDN%  "userWorkstations:-"^|Find "The command completed successfully"') do (                               set UWOK=Y                              )                              if "%UWOK%" EQU "N" goto :EOF                              set UWOK=N                              for /f "Tokens=*" %%a in ('admod -b %userDN%  "userWorkstations:+:%LogonTo%"^|Find "The command completed successfully"') do (                               set UWOK=Y                              )