[asterisk-users] asterisk freeze due to "too many open file" error

[Giorgio Incantalupo]

Hi,
my Asterisk 1.2.9.1 suddenly freezed ("stop now" did not work!!) . I 
found the following errors inside /var/log/asterisk/message:

Feb 14 14:55:41 ERROR[11273] rtp.c: Unable to allocate socket: Too many 
open files
Feb 14 14:55:41 WARNING[11273] chan_sip.c: Unable to create RTP audio  
session: Too many open files
Feb 14 14:55:43 WARNING[11273] acl.c: Cannot create socket
Feb 14 14:55:46 WARNING[11273] acl.c: Cannot create socket
Feb 14 14:56:01 WARNING[11283] chan_misdn.c: Write returned <=0 
(err=Destination address required)
Feb 14 14:59:56 WARNING[13725] res_agi.c: unable to create fromast pipe: 
Too many open files
Feb 14 15:01:21 WARNING[13729] res_agi.c: unable to create fromast pipe: 
Too many open files
Feb 14 15:01:56 WARNING[13744] res_agi.c: Unable to create toast pipe: 
Too many open files
Feb 14 15:01:56 ERROR[13744] cdr_custom.c: Unable to re-open master file 
/var/log/asterisk/cdr-custom/Master.csv : Too many open files
Feb 14 15:01:56 ERROR[13744] cdr_csv.c: Unable to re-open master file 
/var/log/asterisk//cdr-csv//Master.csv : Too many open files
Feb 14 15:02:18 WARNING[13747] res_agi.c: Unable to create toast pipe: 
Too many open files
Feb 14 15:02:18 ERROR[13747] cdr_custom.c: Unable to re-open master file 
/var/log/asterisk/cdr-custom/Master.csv : Too many open files
Feb 14 15:02:18 ERROR[13747] cdr_csv.c: Unable to re-open master file 
/var/log/asterisk//cdr-csv//Master.csv : Too many open files

Considered that the result of ulimit is "ulimited", is there anybody who 
knows how to avoid these errors?

TIA

Giorgio Incantalupo