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Re: Computer systems blamed for feeble hurricane response?

  • From: Steven M. Bellovin
  • Date: Tue Sep 13 17:55:15 2005

In message <20050913212312.GM16110@core.center.osis.gov>, 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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