Allow anonymous participants to dial out

Be carefull if you decide to enable "Allow anonymous participant to dial out" from Skype conference

If you enable this feature, you can experience anonymous users, using your Skype for Business solution to call to countries where it is expensive to call like countrys below.

•         Saint Lucia (+1758)
•         Saint Vincent and the Grenadines (+1784)
•         Cayman Islands (+1345)
•         Grenada (+1473)
•         Dominica (+1767)
•         Turks and Caicos Islands (+1649)


The scenario below can become reality if you have this feature on. It could cost your company a lot of money!


If you know an old URL for a Skype Meeting you can copy/paste the URL in the browser. At the end of the URL you add ?sl=1 to force starting the Skype Web App

Type any name you want and then hit the green button



Click on the partisipants symbol. See red arrow

You can then enter any PSTN number in the world, and then click Call. (The SIP trunk, Dial-plan etc must allow calls to the country)

Who should pay for this call? Yes, you are right, your company! It quickly becomes expensive for your company with this feature on.


You can find this information in Skype Monitoring reports - User Activity Report


1: The user who create the Skype Meeting

2: You will see the Anonymous user, who join the meeting from WepApp as anonymous@anonymous.invalid

3: The PSTN number the Anonymous user call from the conference

Conclusion: Don`t enable this feature!