> Jeff Epler wrote:
> >
> > On Wed, Jul 14, 1999 at 10:57:15PM -0500, Oliver Xymoron wrote:
> > <snip>
> > > Changing the appearance of files on disk is as insane as
> > > transparently changing data in a TCP flow.
> >
> > You mean like ip masquerading can do?
> >
> No. IP masq. changes IP _headers_; he was talking of data.
Yep, as was said, ip masquerading has also to change metadata in a
connection.
For example for active mode ftp you modify the ip address in any port
commands going in ascii through the line. You might call this changing
metadata only, but I don't care for all these hair splitting
theoretical word games, for me it does not really matter if some "port
a.b.c.d\n" string is changed to "port A.B.C.D\n" or if there is CRLF-LF
conversion.
However, TCP streams are different from files. You can only read them
sequentially, so you don't have any problems with different length of
the new and old port command lines, you can't seek TCP streams or mmap
them. Also, you can easily check if the port conversion needs to be done
by identifying the FTP control connection via port numbers. As was said,
for a DOS file, just using the filename to determine if ascii conversion
needs to be done is often insufficient.
Michael.
--Michael Weller: eowmob@exp-math.uni-essen.de, eowmob@ms.exp-math.uni-essen.de, or even mat42b@spi.power.uni-essen.de. If you encounter an eowmob account on any machine in the net, it's very likely it's me.
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