Contoso, Ltd. has a Skype for Business Server 2015 environment that uses open federation. The perimeter network topology is shown in the exhibit. Click the Exhibit button.
The public certificates on the external interfaces of the Skype for Business Edge and Reverse Proxy are as follows:
Audio calls to federated partners that also use Skype for Business Server 2015 are not working.
You need to correct the issue of the failed audio calls.
What should you do?
A. On the reverse proxy external interface, add "contoso.com" as a subject alternative name to the public certificate.
B. On the external firewall to the AV Edge Service External IP address, open the inbound and outbound UDP port 3478.
C. On the external firewall to the AV Edge Service External IP address, open the inbound and outbound UDP and TCP port range 50000-59999.
D. On the external firewall to the Access Edge Service External IP address, open the inbound and outbound UDP port 5061
E. On the reverse proxy external interface, add "lyncdiscover.contoso.com" as a subject alternative name to the public certificate.
Correct B