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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Computer systems blamed for feeble hurricane response?
In message <[email protected]>, Joseph S D Yao writes : >On Tue, Sep 13, 2005 at 04:56:58PM -0400, Joseph S D Yao wrote: >> On Tue, Sep 13, 2005 at 04:28:41PM -0400, Steven M. Bellovin wrote: >> ... >> > Telnet options, and for that matter speed, happen after the 3-way >> > handshake. We're not getting that far. >> > >> > --Steven M. Bellovin, http://www.cs.columbia.edu/~smb >> >> Steve, I defer to your expertise, as always. ;-] > > >Nevertheless ... I went looking for comments on how this was being done, >and found the following specualtion by a small number of different >people. > >"SEF [is] unique in that it can detect what appear to be telnet >connections to Port 25 and drop the connection. This is probably because >telnet connections send one character at a time whereas real SMTP >clients send all the strings at once." > >This would not require the 3WH, ISTM. > Sure it would -- until the 3-way handshake, there's no application data flowing, and hence no characters being sent one at a time. We'll leave to another mailing list the question of what security benefit there is to such a feature... --Steven M. Bellovin, http://www.cs.columbia.edu/~smb
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