asterisk users - Jan 2011 - Weird phone behavior after recent CentOS 5 update

For some reason our Asterisk box is doing something really unusual following
applying a routine update to CentOS 5 on Monday.

We have Asterisk 1.4.2 and its been working great for years.  But now when the
phone system receives an incoming SIP call, its not providing any audible dial
sound to any caller.  It is recognizing the incoming call, and after no answer
for about 5 rings or so, it goes to voice mail.  But there is no audible
'ring' to the caller.  Just nothing - blank, empty silence.

Of course any automated answering system (ie. business phone menu, etc.) that we
have works just fine.  Its just the lines that go directly to an internal phone
that are no longer providing any audible ring which is sending a message to the
caller that their call didn't go through.

Does anyone have any idea what might cause this?

Myles

Some more info on this weirdness....

Seems that if I play any audio out from Asterisk first the problem goes away. 
its almost like the entire audio engine isn't being 'initialized' or
something on those direct calls.  I found that if I execute a Swift(Please Wait)
before I call the Dial command in my extensions, then it plays the ringing tone
as expected.  But if I receive a call, and then try and have it transferred
directly to a phone extension via a Dial command (which used to work perfectly
well), the calling party never hears a ringing tone.  But if I play some audio
purposely before, then it rings....

Myles

On Wed, Jan 5, 2011 at 6:59 PM, Myles Wakeham <myles at techsol.org>
wrote:
> For some reason our Asterisk box is doing something really unusual
following applying a routine update to CentOS 5 on Monday.
>
> We have Asterisk 1.4.2 and its been working great for years. ?But now when
the phone system receives an incoming SIP call, its not providing any audible
dial sound to any caller. ?It is recognizing the incoming call, and after no
answer for about 5 rings or so, it goes to voice mail. ?But there is no audible
'ring' to the caller. ?Just nothing - blank, empty silence.
>
> Of course any automated answering system (ie. business phone menu, etc.)
that we have works just fine. ?Its just the lines that go directly to an
internal phone that are no longer providing any audible ring which is sending a
message to the caller that their call didn't go through.
>
> Does anyone have any idea what might cause this?
Definitely check your firewall settings.

Definitely consider rebuilding against the libs as they now exist on
your machine. CentOS (which are really RedHat) library changes aren't
always fully disclosing the things that actually change.

The worst example in recent memory was when a CentOS update changed
the defaults to sudo, and you had to go manually override to allow
sudo to work without a tty.