Lync 2013 Meeting Options Policies

Lync 2013 default meeting options can be configured at the global or site level. These setting effect scheduled meeting options (for example in Outlook as shown below); they do not affect ad-hoc meetings created by clicking the Meet Now option in Lync. When you create a meeting by clicking Meet Now, participant access is automatically open to all everyone, and anonymous users can join the meeting without having to wait in the lobby.
Meeting Security
It’s worth making a special note of the AssignedConferenceTypeByDefault setting, as it’s likely to raise security concerns for most. The default of $true creates scheduled meetings as public by default (although the user can change this themselves while creating the meeting), meaning the conference ID and the meeting link remain consistent each time the meeting is held. By changing this setting to $false you can set the default to private, which means the conference ID and meeting link changes from meeting to meeting. The latter is more secure, as there is less risk that someone accidentally join the wrong meeting.

Policy Configuration
To get the current Global policy run Get-CsMeetingConfiguration or specify the site to get a site policy Get-CsMeetingConfiguration -Identity site:<site>
Modify Global Policy
e.g. Set-CsMeetingConfiguration -AssignedConferenceTypeByDefault $false

Modify Site Policy
Set-CsMeetingConfiguration -Identity site:<site>
e.g. Set-CsMeetingConfiguration -Identity site:Auckland -AssignedConferenceTypeByDefault $false

Create New Site Policy
New-CsMeetingConfiguration -Identity site:<site>
e.g. New-CsMeetingConfiguration -Identity site:Auckland -AssignedConferenceTypeByDefault $falseThe following options are available on the above commands:

Determines whether meetings will, by default, allow attendance by anonymous users/unauthenticated users. Set this value to $true if you would like new meetings to allow for attendance by anonymous users by
default. Set this value to $false if you would prefer that, by default, new meetings do not allow for attendance by anonymous users. The default value is $true.

Determines whether new meetings will be configured, by default, as public meetings. Set this value to $true to use public meetings by default; set this value to $false to use private meetings by default. The default value is $true, however $false would be more secure creating a new meeting space for each meeting. To disable public meetings altogether use EnableAssignedConferenceType mentioned below.

Text to be used on custom meeting invitations.

Indicates which users (besides the meeting organizer) are automatically designated as presenters when they join a meeting. Valid choices are: None; Company; and Everyone. By default, DesignateAsPresenter is set to Company, meaning everyone in your organization will have presenter rights the moment they join a meeting.

Indicates whether users are allowed to schedule public meetings. The default value is $true.

URL to a website where users can obtain assistance on joining the meeting.

URL to a website containing legal information and meeting disclaimers.

URL for the image to be used on custom meeting invitations.

Indicates whether users dialing in over a public switched telephone network (PSTN) phone line should automatically be admitted to a meeting. If set to $true, PSTN callers will automatically be admitted to the meeting. If set to $false, then PSTN callers will initially be routed to the conference lobby. At that point, they will have to wait, on hold, until a conference presenter grants them access to the meeting. The default value is $true.

When set to $true all users must be authenticated before they can join a meeting using the Lync Room System. The default value is $false.