Packets lost

["Vasantha Kumar Puttappa" <vasanthakumar@iitb.ac.in>]

Hi All,
 Please somebody guide me here.

I am tracking all udp packets (in particular, SIP based UDP packets)that
goes through iptables using LOG mechanism.
I use the following command,
    iptables -A INPUT -p udp -j LOG --log-level-4.

In addition, i also run 'Ethereal' to make sure that all the packets
captured goes through iptables as well.

Here is the problem,
  Sometimes, a random number of packets doesnot go through IPtables and
they are completely lost. Although, I can see those packets in Ethereal.

 I tried increasing the backlog queue and ip_queue length, but still no use.
 I am using Netgear's wireless network card (WG511, made in taiwan).


 Somebody please guide me. How do I findout the cause of this.

 Regards
 Vasanth