TCP time_wait and port exhaustion for servers

Thu Dec 6 04:29:22 UTC 2012

On Wed, Dec 5, 2012 at 7:49 PM, Mark Andrews <marka at isc.org> wrote:
> counter: dest address in hex
>
> 16376: 1a003ff9
> 16377: 1a003ffa
> bind: before bind: Can't assign requested address
> 16378: 1a003ffb
> connect: Can't assign requested address
> bind: before bind: Can't assign requested address
>
> and if you remove the bind() the connect fails
>
> 16378: 1a003ffb
> 16379: 1a003ffc
> connect: Can't assign requested address
> 16380: 1a003ffd

Tried it. When I removed the bind() I made it to a quarter million
connections before I ran out of ram on the test machine and the out of
memory killer swung into action. Don't know what your problem is.

  for (count=0; count<1000000; count++) {
    s=sockets[count]=socket(AF_INET,SOCK_STREAM,0);
    if (s<0) {
      printf ("\nCould not get socket #%d\n",count);
      sleep (900);
      return 1;
    }
    if (connect(sockets[count], (struct sockaddr *) &sa, sizeof(sa))<0) {
      if (errno != 115) {
        printf ("\nErrno %d on socket #%d\n",(int) errno, count);
        sleep (900);
        return 1;
      }
    }
    sa.sin_addr.s_addr = htonl(ntohl(sa.sin_addr.s_addr)+1);
    now = time(NULL);
    if (now!=before) {
      before=now;
      fprintf (stdout,"%d\r",count);
      fflush (stdout);
    }
  }

Regards,
Bill Herrin

-- 
William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
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