Multiple OBi's Call/Rings/Answer/Nothing

[cycleman]

Hello,
This is my first newbie post... I will try to make myself clear:
. have multiple OBi's, with different internet service providers
. all are very simple by the book setup with SP1 with their own Google Voice
. all was working well (for weeks) till recently
. The problem is on multiple OBi's that are using SAME internet provider, any calls to any POTS number (including other OBi's Google voice): it rings on the other side but when it is picked up, one of 2 things may happen: 1. both parties hear nothing - dead silence. or 2. the calling party keep hearing the "ringing tone" even when the destination has been picked up !!
. Please note, when calls are made from/to other OBi's than the "ONE" internet provider: All works perfectly...
. Also, Please note that OBi calling (using **9OBi#) always works and calls can be answered and heard well

I suspect, the internet provider of this set of my OBi's has implemented a firewall of some kind and blocked some ports .... (which i can do NOTHING about)

any idea, is there a way to change any of the pre-configured default ports to make it work?

Thanks in advance

[Shale]

Care to name the provider? That would be useful for others who don't have the resources and resourcefulness to identify why the symptom is occurring.

In answer to your question, change the (Voice Services)SPn Service->X_UserAgentPort ports for each SPn to a number not in the 506x range. Pick something that will not conflict with something else you use. http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers You may find discussion of people changing this port to make it harder to be discovered by SIP scanners.

Maybe you will need to change X_KeepAliveServerPort also. I am thinking probably not. I don't know exactly what this is used for, but I suspect it may have to correspond to what the corresponding SIP provider uses.

[cycleman]

Thank you for your reply, I will look into the thread provided for additional info.
I do not know the name of the internet provider used with the OBi in question, this setup is in Syria and I am remotely unaware of such detail.
Thanks again, will try your recommendation