Re: Re-routing packets via netfilter (ip_rt_bug)

From: Patrick McHardy
Date: Wed Apr 27 2005 - 07:06:55 EST

Herbert Xu wrote:
Here is another reason why these packets should go through FORWARD.
They were generated in response to packets in INPUT/FORWARD/OUTPUT.
The original packet has not undergone SNAT in any of these cases.

However, if we feed the response packet through LOCAL_OUT it will
be subject to DNAT. This creates a NAT asymmetry and we may end
up with the wrong destination address.

By pushing it through FORWARD it will only undergo SNAT which is
correct since the original packet would have undergone DNAT.

This is only a problem since the recent NAT changes, but I agree
that we should fix it by moving these packets to FORWARD.

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