Re: Packet Lost

[Patrick McHardy <kaber@trash.net>]

Vasantha Kumar Puttappa wrote:
> Hi,
> 
>   I am working on a small application using iptables/libipq. In this, the
> application would capture a specific packets based on the destination IP
> address. Then I encapsulate this IP packet inside another new IP packet.
> 
> My problem is that the encapsulation part works fine in
> kernel-2.6.11-6(mandriva 2005) and IPtables V 1.2.9.
> (I can capture encapsulated packets using tcpdump at the sender side i.e,
> packets are being put on to the network)
> 
> 
> But this doesn't work in kernel-2.6.12-12 and IPtables-1.3.5
> (even though there are no erros after callig ipq_set_verdict, the packets
> are not being put on to the channel. The packets are getting lost after
> the call to ipq_set_verdict)
> 
> please let me know if you need more information

IIRC some old versions accidentally fixed up broken checksums
they received from userspace and this is not done anymore.
Do your packets have correct checksums when sent from userspace
to the kernel?