You support a Microsoft Lync Server 2013 environment with open federation for a company named
Contoso. Contoso’s perimeter network topology is shown in the exhibit. (Click the Exhibit button.)

The public certificates on the external interfaces of the Lync Edge and Reverse Proxy are as follows:

You receive a support ticket that audio calls to federated partners that also use Lync Server 2013 are
not working. You need to correct the issue of the failed audio calls. What should you do?

A.
Add “contoso.com” as a subject alternative name to the public certificate on the reverse proxy
external interface.

B.
Add “lyncdiscover.contoso.com” as a subject alternative name to the public certificate on the
reverse proxy external interface.

C.
Open the inbound and outbound UDP port 5061 on the external firewall to the Access Edge
Service External IP address.

D.
Open the inbound and outbound UDP and TCP port range 50000-59999 on the external firewall to
the AV Edge Service External IP address.

E.
Open the inbound and outbound UDP port 3478 on the external firewall to the AV Edge Service
External IP address.