[tproxy] Connection refused on already accepted connections

[jan@tegtmeier.de]

Hi again,

when using tproxy, all outgoing connections are redirected to the proxy 
application. This proxy accepts the connection. After the connection is 
established, the proxy get get the real target with getsockopt. Now it 
connects to the real target by itself. 

What happends, if the target rejects the connection, is unreachable or has 
other problems? The 3way connection handshake between client and proxy is 
already established and the client must think, that the connection is 
established with the real target, as tproxy is transparent. 

The only way I see is to close the connection so the client will get a 
"connection closed by foreign host". They cannot distinct between different 
connection problems. Not very nice!? Maybe some applications will have 
problems with this behaviour? 

Nice day,
 Jan Tegtmeier