Port Number Assignation; Is It Safe - Polycom ViaVideo Technical Reference

Chapter 3
ViaVideo Technical Reference
For information on opening and assigning ports in the firewall, see
"Router With Firewall" on page 11.

Port Number Assignation

ViaVideo has applied with the Internet Assigned Numbers Authority
(IANA) for the default range of 6 ports: 3230 - 3235. You must also
assign port 1720 to ViaVideo so you can receive incoming calls.
We recommend that you use the default range of ports for both TCP
and UDP packet transfer. If you wish to assign a different range of
ports, you can specify any registered, non-assigned ports in a 6-port
range to ViaVideo. For a list of registered, non-assigned ports, go to:
http://www.isi.edu/in-notes/iana/assignments/port-numbers.
When you assign the ports to the ViaVideo application, the router
reserves the assigned ports for use by ViaVideo.

Is it Safe?

The short answer is: "Safe enough." Like any other defense, there's
no such thing as a perfect firewall. Whenever you are connected to
the outside world, there is always some risk that someone could gain
unauthorized access. The need for protection must be balanced
against the need to communicate with the outside world. This is why
most security solutions focus on minimizing the risk until it reaches
an acceptable level.
Opening ports in the firewall might seem at first like an unnecessary
security risk. However, there are in reality so many ports (65535
that simply discovering which port might be open is difficult enough.
In addition to the sheer number of ports, protections written into the
operating system make it very difficult to gain unauthorized access
to your network, even if those ports are open. Finally, only port 1720
is open to receive incoming requests. The range of six ports is only
open in your PC during a call.
If "safe enough" isn't secure enough for you, then setting your
ViaVideo up in a DMZ is safer option. For more information about
DMZs, see the next section.
18
Network Connection
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