Prevents users from adding directory (ILS) servers to the list of those they can use for placing calls.
| Registry Hive | HKEY_CURRENT_USER |
| Registry Path | Software\Policies\Microsoft\Conferencing |
| Value Name | NoAddingDirectoryServers |
| Value Type | REG_DWORD |
| Enabled Value | 1 |
| Disabled Value | 0 |