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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.
> Besides, we found that the originator of this thread was
> really just trying
> to ensure that undesired mail relaying couldn't happen. As he
> later discovered, the use of telnet doesn't make this any more
> possible than it is with a normal mail client.
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.
Regards,
Frank
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