[asterisk-dev] Asterisk freezes because cannot create no more sockets

[Giorgio Incantalupo]

Hi,
I have an Asterisk 1.2.9.1 on a Debian Sarge box with an ISDN beronet 
card. Sometimes my Asterisk frezees and user complain they cannot 
make/receive calls. I took a look inside messages log file and I saw 
errors like this:

WARNING[21701] res_agi.c: unable to create fromast pipe: Too many open files
WARNING[2894] acl.c: Cannot create socket
ERROR[21971] rtp.c: Unable to allocate socket: Too many open files
WARNING[21971] chan_sip.c: Unable to create RTP audio  session: Too many 
open files
ERROR[21971] chan_sip.c: Unable to build sip pvt data for '1' (Out of 
memory)
NOTICE[21971] app_dial.c: Unable to create channel of type 'SIP' (cause 
42 - Switching equipment congestion)
WARNING[2894] acl.c: Cannot create socket
...

Before restarting Asterisk I typed lsof getting a lot of lines like this 
(about 1000 lines):
asterisk  31417 asterisk 1021w     FIFO        0,5              749130 pipe
asterisk  31417 asterisk 1022w     FIFO        0,5              749266 pipe
asterisk  31417 asterisk 1023w     FIFO        0,5              749285 
pipe    <---last one of my output!

It seems that asterisk is creating pipes for some unknown (to me) reason.

Is there anybody who knows what is creating all these pipes? I'd like to 
avoid a scheduled "restart now" every day (smells like Microsoft style...)
Consider that we have many PBXes but this strange phenomena seems to 
happen only with ISDN (we have Asterisk Boxes with PRI cards but got no 
problems at all even with a lot of calls per minutes).

Thanks for patience.

Giorgio Incantalupo