Packets lost

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

Vasantha krishna Puttappa írta:
> 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.
>   
Maybe you also need the following rule:
iptables -A FORWARD -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.
>   
Ethereal sees the packets BEFORE iptables.
So maybe some of your rules drops the packet.
> 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
>   
Swifty

Hi Lajos,
 Thanks for responding so fast. I did try adding the forward
rule, but
still packets are missing.
 Let me give you more insight into what I am trying do.
 I have a vitrual network interface and 2 physical network
interface (one
Ethernet based, and other 802.11 based). The virtual network
interface
dynamically binds to any one of the above physical
interfaces for packet
transmission. The issue of packet loss occurs **only**
during link
switching.

I feel that the following issues might be the possible
reasons for the
packet loss.

1. Due to missing soft_IRQ interrupt for packets and hence
packet loss ( i
have no proof to back this)
2. Due to incompatible wireless device driver.


Any thoughts on this ?








> Vasantha krishna Puttappa írta:
>> 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.
>>
> Maybe you also need the following rule:
> iptables -A FORWARD -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.
>>
> Ethereal sees the packets BEFORE iptables.
> So maybe some of your rules drops the packet.
>> 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
>>
> Swifty
>
>

Vasantha krishna Puttappa írta:
> Hi Lajos,
>  Thanks for responding so fast. I did try adding the
forward rule, but
> still packets are missing.
>  Let me give you more insight into what I am trying
do.
>  I have a vitrual network interface and 2 physical
network interface (one
> Ethernet based, and other 802.11 based). The virtual
network interface
> dynamically binds to any one of the above physical
interfaces for packet
> transmission. The issue of packet loss occurs **only**
during link
> switching.
>   
What is this "link switching" in real ? What about
routing and source 
addresses ?
> I feel that the following issues might be the possible
reasons for the
> packet loss.
>
> 1. Due to missing soft_IRQ interrupt for packets and
hence packet loss ( i
> have no proof to back this)
> 2. Due to incompatible wireless device driver.
>
>
> Any thoughts on this ?
>   
What if you use a bridge on those three and the condition
extension of 
iptables?

Swifty