asterisk users - Jun 2005 - RE: Call being answered, but no audio on either end

I think I found the source of this.  Been tracing it for a week.  Look in
sip.conf.  It appears the definition of localnet has a bearing on how some
sip devices handle invites and NAT.

I had changed the localnet to 192.168.3.0, but did not change the netmask.

localnet=192.168.3.0/255.255.0.0; All RFC 1918 addresses are local networks

When I changed the netmask to 255.255.255.0 the problem appeared to go away.
It appears the more restrictive localnet the better results at handling sip
devices behind NAT devices.

Gene 
>   19. Call being answered,	but no audio on either end
>       (Intermittent) (Geoff Manning)
> ------------------------------
> 
> Message: 19
> Date: Tue, 14 Jun 2005 17:30:31 -0400
> From: Geoff Manning <gmanning@zoom.com>
> Subject: [Asterisk-Users] Call being answered,	but no audio on
either
> 	end (Intermittent)
> To: "Asterisk Users (E-mail)"
<asterisk-users@lists.digium.com>
> Message-ID:
> 	<D1696C471C6CD511A0BE00D0B7A932DE0957C97C@southe01.zoomtel.com>
> Content-Type: text/plain;	charset="iso-8859-1"
> 
> The best type of error possible, intermittent.
> 
> We have PSTN numbers being switched to SIP then forwarded to our Asterisk
> server which sits inside our LAN
> 
> Every once and a while (maybe 1 out of every 20 calls) goes like this:
> 
>     -- Executing Answer("SIP/213.199.36.50-0818e3e8",
"") in new stack
>     -- Executing Ringing("SIP/213.199.36.50-0818e3e8",
"") in new stack
>     -- Executing Dial("SIP/213.199.36.50-0818e3e8",
"ZAP/g1/:8213") in new
> stack
>     -- Called g1/:8213
>     -- Zap/1-1 answered SIP/213.199.36.50-0818e3e8
>     -- Hungup 'Zap/1-1'
>   == Spawn extension (from-gv-uk, 441252580625, 3) exited non-zero on
> 'SIP/213.199.36.50-0818e3e8'
> 
> Looks normal right? During this whole exchange, neither side can hear the
> other. Not even a ringing sound.
> 
> The above looks no different than the successful calls.
> 
> Has anyone seen this type of behavior before?
> 
> Thanks!
> 
> 
> ------------------------------