Need fast reply: how does iptables interact with kernel space code ??

[Sergei Lavrov]

Hi,

I went through some of the iptables code because I
want to understand how iptables interact with the
kernel space.

For example, the following command redirects all the
web traffic to the local port 10080.

iptables -t nat -A PREROUTING -i ppp0 -p tcp -j
REDIRECT --to-port 10080 --dport 80

I went through extensions/ipt_REDIRECT.c and
libiptc/libiptc.c and libiptc/libip4tc.c.

But I still don't understand what iptables does to the
kernel so that the kernel will redirect the traffic ?
Exactly, what does iptables communicate to the kernel
? Can someone explain the gist to me ??

For understanding of the kernel side, should I read
iptable_filter.c, ip_nat_standalone.c, or
ip_nat_rule.c ??

Thanks,

Sergei


 
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