At 23:17 23/08/00 -0500, Frank Knobbe wrote:
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> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, August 23, 2000 9:42 PM
> >
> > [...]
> > The other is even more obvious. Most, if not all, telnet clients
> > will attempt to perform telnet option negotiation at the beginning
> > of a connection. [...]
>
>True, except Netcat does not do this unless you tell it to.
and with a perl script, and with a C program, ...
The SMTP protocol specifies how it works, it doesn't give a list
of registered programs to be used!
>Agreed. One last note, though. SMTP email originates on port 25.
>Telnet usually originated on a high-port (unless you use netcat...
>dang, this handy little tool :) Anyway, to thwart of the curious,
>one can just construct his firewall rule to only allow traffic to
>port 25 if it originates from port 25. Seems to hide it from most
>port scans as well.
no. 25 is the destination port, the well-known server port. Client ports
are random ports. Also, if 25 was the client port, then the client must be
run as root (On Unix), which would be a silly requirement.
regards,
mous
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