What port should Vickiblock at the firewall so no external connections can be made directly to the VoIP phones?

Vicki is the IT manager for her company, an online retail business in Seattle. Vicki was recently given budget approval by the CIO to purchase 100 VoIP phones and all the VoIP networking equipment needed to make a complete VoIP implementation. Vicki and her employees install all the phones and set up the serversneeded to run the new system. After about three months of setup, everything hasbeen completed and the system is finally stable. Because she is not very familiar with VoIP security, she attends a VoIP security seminar which she finds very informative. One interesting piece of information she learns of is that most VoIP phones are installed with an imbedded OS called VxWorks. This, she finds out, is also what the VoIP phone manufacturer installed on all her company’s new VoIP phones. Vicki also learns that there is a default remote debugger on all these phones that listens on a specific port in case a remote administrator needs to do some troubleshooting. Vicki sees this as a large security problem. Instead of going to each and every new phone to turn off this feature, she decides toblock the necessary port on the firewall to save time. What port should Vickiblock at the firewall so no external connections can be made directly to the VoIP phones?

A.
Vicki needs to block TCP port 17185 at the firewall to prevent the default debugger program from communicating outside the network.

B.
She should block UDP port 21972 at the firewall to keep the remote debugging feature on the VoIP phones from being used.

C.
TCP port 9121 should be blocked at the firewall to keep anyone from using the remote admin debugging software.

D.
She needs to block any traffic on the firewall coming in on or going out on TCP port 4290.