Re: Fun with IP Identification Field Values (Identifying Older MSBased OSs)

["Crist Clark" <crist.clark () globalstar com>]

Denis Ducamp wrote:

[snip]

> Now some systems protects against been used to spoof-scan :

[snip]

>  . Linux 2.4.x : IPID is null if the packet is small enought to be carried
>    unfragmented in which case the DF (don't fragment) bit is set
>  . others perhaps ?

Ah-ha!!! So that might be the cause of those bizarre signatures I have
been seeing. Can anyone point me to documentation of this 
Linux-IP-stack-of-the-week feature? Would this and ECN (what looks to
me like broken ECN) account for,

  http://www.securityfocus.com/archive/75/178231

-- 
Crist J. Clark                                Network Security Engineer
crist.clark () globalstar com                    Globalstar, L.P.
(408) 933-4387                                FAX: (408) 933-4926

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