Re: non-random IP IDs

[Mike Silbersack]

On Mon, 16 Apr 2001, Julian Elischer wrote:

> there is a site that calculates server uptime from these numbers.
> All the leading machines are freeBSD. When you do this it will
> no-longer be able to track us :-(

They're using TCP timestamps to do that, not ip ids.  And if I get my way,
those will be unuseable for uptime detection soon enough... :)

> what is the problem in having these numbers sequential?

Anonymous port scans, some firewall probing as mentioned by darren, and
the ability to see the idleness of a host.  Not enough to make
randomization the default policy, but certainly enough to justify a
sysctl.

Mike "Silby" Silbersack


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