[asterisk-dev] Problems with Firewall

[Steve Totaro]

On Mon, Feb 2, 2009 at 11:50 AM, Steve Totaro
<stotaro at asteriskhelpdesk.com> wrote:
> On Mon, Feb 2, 2009 at 11:43 AM, Karsten Asche <K-Asche at web.de> wrote:
>> Hi @ all,
>>
>> IŽm programming a Softphone under Windows.
>> At the moment I have the problem if I do a call,
>> the SIP Session will be created succesfully but sometimes
>> the speech from my XP System will be send but after send to server
>> it will be blocked.
>> The curiosity is that under Vista this problem doesnŽt happen.
>> Both Clients run through the same Firewall.
>> If i Do the call on my XP with SJPhone it works fantastic and after
>> compare the sent pakets with my sent pakets there are no differences.
>>
>> What could it be?
>>
>> Regards
>> Karsten
>>
>
> Port forwarding, NAT, two phones on 5060?
>
> --
> Thanks,
> Steve Totaro
> +18887771888 (Toll Free)
> +12409381212 (Cell)
>

Maybe explain the topology a bit more.....

If your softphone is not sending an occasional keep-alive through the
firewall, then the firewall may take i as an unsolicited packet and
block it.  Different firewalls/routers have different timing, but you
need to be sending keep-alives to keep the dialog open when the phone
is not in use.

Just a thought....

-- 
Thanks,
Steve Totaro
+18887771888 (Toll Free)
+12409381212 (Cell)
+12024369784 (Skype)