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If you use MS Exchange and Outlook in your organization there are tools for sharing free/busy information between Exchange and 3e. Besides being able to get free/busy from 3e service you will be able to get free/busy from all other calendar services supported by 3e which currently includes Bedework, DAViCal, Horde, IceWarp, Kerio, Google, and VMWare Zimbra.

Freebusy for Exchange

Freebusy for Exchange is a Windows service which enables meetings planning among users of 3e and MS Exchange and other calendar services by providing free/busy information.


  1. Download installer from here ZonioFreebusyForExchange.exe.
  2. Run the installer.
  3. Make appropriate changes in settings file. See configuration below.

  4. Start the service.

    From now on the service will be started automatically on system boot.


Configuration consists of:

Configuration file options

Default location of configuration file is C:\Program Files\Zonio\Zonio Freebusy for Exchange.


Service account which logins to Exchange to access free/busy information.


Password for service account.


Url used to connect to Exchange. Default format is

If you are not sure what your EWS url is you can check by type following into PowerShell:

freebusyListen & eeeListen

Sets where to listen for Outlook clients & users outside your organizetion requesting free/busy respectively. You can specify multiple interfaces and use wildcards for ip. Format for values is same for both directives.

(warning) When you change interfaces to listen on you must bind certificate to new interfaces and update service discovery. See Set listening interface and Service Discovery.



Number of threads processing incoming requests.

isFreebusyInfoCertificate & isFreebusyInfoPrivateKey

Path to certificate & private key used to access service which provides a. Default with some limitations is provided. If you bought license you need to either change these values or rewrite files.

Default pair is stored in installation folder.


How long service remembers free/busy information for requested attendees in seconds.

Service discovery

You can choose from two options to be discoverable via DNS or via well-known URI. We recommend to setup both methods. It should be generally more reliable as some of the client applications may use only one of them. For example web applications would probably tend to prefer well-known URI over DNS.


Create TXT record for domain of the organization. This is the domain users have in their email addresses ie. if your organization email address look like Add new TXT record and point it to the hostname and port where you Zonio FreeBusy Connector is running.

To add TXT record run following command:

(warning)If you use Windows PowerShell don't forget to escape @ with grave accent `.

Alternatively you can use GUI tools to set record.

Well-known URI

Create a file which is accessible through HTTP on your organization's domain in location /.well-known/eee. Usually this is the domain which the users have in their email addresses ie. if your organization email address look like Create a file on which points to the hostname and port where you Freebusy for Exchange is running. The content is the same as in DNS record, but just without eee in the beginning.

Set listening interface

By default Freebusy for Exchange listens on all addresses on port 4444 to incoming outside free/busy requests and on port 8080 for Outlook clients within your organization . If that doesn't fit your needs you can change that.

To update listening interface follow these steps:

  1. Unbind certificate from old interface

  2. Bind certificate to new interface (set address and port according to your preference). Address means that certificate will be bound to all addresses (both IPv4 and IPv6) with given port.

    If you want to bind certificate with IPv6 address specify it within square brackets:

    (info) Values for certhash and appid keep the same as in this example.
    (warning) If you use PowerShell do not forget to escape curly braces with grave accent `.

  3. Update configuration file if you haven't done it yet.

  4. Update DNS for service discovery. See Service Discovery above.

Outlook free/busy provider

To be able to obtain free/busy information from 3e and other calendar services from Outlook you need to install free/busy provider. This provider then asks Freebusy for Exchange for free/busy information so you must have instance the service running. See Freebusy for Exchange above.


  1. Download installation package for 64bit Outlook or 32bit Outlook.
  2. Install the provider.
  3. Set location where Freebusy for Exchange service is listening to Windows registry as a string value in format <domain>:<port> to key HKEY_LOCAL_MACHINE/Software/Zonio/ZonioFreebusyForOutlook.


    Now you can plan with people from 3e and many other calendar services. Just create an appointment, open Scheduling assistant and type emails of users you want to invite.

  4. Edit log level if necessary. Possible values are none or debug. Log output is in C:\ProgramData\Zonio\ZonioFreebusy.log.
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