[tproxy] netcat for tproxy (and additional noob questions)

KOVACS Krisztian hidden at sch.bme.hu
Tue Jul 7 14:02:32 CEST 2009


On Tue, Jul 07, 2009 at 07:49:17AM -0400, John Lauro wrote:
> > I have a very simplistic patch for netcat here:
> > 
> > http://home.sch.bme.hu/~piglet/netfilter/tproxy/netcat-ip_transparent-
> > support.patch
> I think I came across that patch before.  The problem is I can not find that
> version (1.10) of netcat anywhere.  Found some places that mention being
> pointers to it, but dead links...  It appears there a new GNU version that
> has lower version number, and also a BSD version, but it is way different
> too (or at least different enough that the patch doesn't apply).

I think it was based on Debian netcat, so you could give the Debian
version a try:


> > Reusing the original port is usually a bad idea. A notable example of
> > things breaking is Netfilter connection tracking, which gets confused
> > if
> > you reuse the exact same endpoints for a different connection.
> Technically they are not the exact same if you include the interface.  If it
> doesn't consider the interface then they would appear the same.

Netfilter conntrack is interface agnostic -- and you're right that it's
exactly that what's causing the problem here.

KOVACS Krisztian

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