Re: How does iptables redirect a packet that is not addressed to its local machi

["Grace Li" <zheyinli@hotmail.com>]

Yes, Client and Server are in the same network!

I used the Ethereal tool, which is similiar to but better than tcpdump.  On 
Client, Server and Gateway, I could all always see that packets are sending 
back and forth from Server and Client.  There is no sign that Gateway 
receives packets on port 1888 or 2000.

Thanks,

Grace


>From: wanghtb@legend.com.cn
>To: netfilter-devel@lists.netfilter.org
>CC: zheyinli@hotmail.com
>Subject: Re: How does iptables redirect a packet that is not addressed to 
>its local machine
>Date: Thu, 8 Apr 2004 09:47:15 +0800
>
>Hi, I wonder if the Client and the Server are in the same network,
>under which the Gateway will send a ICMP Redirect message to
>make the Client access Server directly. version is iptables
>
>Please check netmask of the Machines and use tcpdump packet in the
>Gateway to see what happens:-)
>
> >Hi,
> >
> >I am just wondering if anybody could explain what happened in the =
> >following experiments:
>
> >Client (192.168.1.134) tries to connect to port 1888 of Server
> >(192.168.1.115) through Gateway (192.168.1.1).  In the Gateway, the =
> >iptables
> >has been instructed to redirect traffic on port 1888 to 2000 (iptables =
> >-t
> >nat -A PREROUTING -i eth0 -p tcp --dport 1888 -j REDIRECT -to-port 2000 =
> >).
> >
> >The results of my experiments is that the application on Gateway who =
> >listens
> >to port 2000 could not get anything, while Server receives everything
> >expected on its port 1888. So my question is that did iptables do =
> >anything
> >here?
> >
> >Many thanks,
> >
> >Grace
>

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