connexion hanging for a moment

Hi, we have from time to time at random a hanging connexions with our Informix 11.70 C5 database, in fact we can"t sometimes access the database even from the server with "dbaccess mydbname", the telnet ont the port works well, the ping is also working but sometime block the connexions sometime for 1 mn and sometimes for more than that , in the online.log we finf at the moement of the hanging these lines: Unable to initiate asynchronous read operation 09:31 AM listener-thread: err =-25580: oserr = 64: errstr =: System error occurred in network function. System error = 64. and suddenly it(s relaesed and than the dbacces to database work and the clients starts working. is that an attack ? here is my config for connexions: (I can reach 4000 concurent connexion) NETTYPE soctcp,4,200,CPU LISTEN_TIMEOUT 60 MAX_INCOMPLETE_CONNECTIONS 1024 FASTPOLL 1 NS_CACHE host=900,service=900,user=900,group=900 I suspected the Io long (checkpoints) but it seems sometimes we have a juste a little ckpt at the hanging time. plz could you advice for the best setting to avoid the problem, and how can I analyse this phenomena

I assume "everyone" is connecting via TCP? If they're using shm connection (which is rare now) and you don't have NETTYPE defined, hard limit is 50. Behavior sounds right, error msgs don't. Just a thought. Mark Scranton mark@markscranton.com The Mark Scranton Group

The problem is that arrive at random, and the time its begin to arrive is often in the morning between 08 AM and 11 AM ans the connexions at this time are normal, maybe its a problem of attack for the port. I will change the protocol to net instead of cpu but what is the right parameter to put , I have 4000 users max.