Network Security - VoIP

Looking for a good explanation of how this section is to be used correctly. The Help section basically just gives the definition of SIP.

SIP Server Networks: I've got my SIP Provider IP here

SIP Client Networks: I've got my Internet Network here

1) Since there is no Automatic Firewall Check Box, am I to assume that this is to simple handle Outbound SIP Traffic to my SIP Provider?

2) Since there is no Firewall rule or NAT Translation, I would assume that I also need to have a DNAT Rule to allow my SIP Provider to be able to contact my Phone System.

3) External SIP Clients and Softphones - There also use 5060 for SIP and need access to my Phone System to establish a SIP Connection. This also usually needs UDP ports 10000 to 20000 opened.(Yes I know that this isn't recommended)

I'm just trying to wrap my head around how this Network Security - VoIP section fits into the puzzle when allowing traffic from the Provider and the Softphone Clients.

Any help would be great, be I would really appreciate someone that really know this section to respond, that way we're not simply guessing.

Thanks,

Steve Weber
CDN Partners, INC