[Fwd: Re: [Ticket#2008110410001492] www.shiningsilence.com reported operating system]

[Justin C. Sherrill]

Here's a question: is there a clear way to tell the difference between a
FreeBSD system and a DragonFly system based on the TCP packets?  (see
forwarded mail below for why I'm asking.)




---------------------------- Original Message ----------------------------
Subject: Re: [Ticket#2008110410001492] www.shiningsilence.com reported   
operating system
From:    "Netcraft Webmaster" <webmaster at netcraft.com>
Date:    Wed, November 5, 2008 7:53 am
--------------------------------------------------------------------------


"Justin C. Sherrill" <justin at shiningsilence.com> wrote:

> The hosting history for www.shiningsilence.com:
>
> http://uptime.netcraft.com/up/graph?display=uptime&site=www.shiningsilence.com
>
> reports FreeBSD as the hosting operating system.  It is actually running
> DragonFly BSD, which forked from FreeBSD in 2003, so they probably look
> very similar.
>
> I don't know a clear way to tell the difference, in part because I don't
> know how you are identifying the operating system now.  This is pretty
> minor as these things go, but it would be nice to have it ID'd correctly,
> as I'm a developer for DragonFly and want to show that I'm willing to eat
> my own dog food, so to speak.

We detect the operating system based on characteristics of the TCP packets
received from the server when making HTTP connections. Probably the TCP/IP
stack of DragonFly BSD is little changed from FreeBSD; it looks just like
FreeBSD to us. If you're able to suggest any differences in the TCP stack,
we could take a look at adding detection.

The only thing that might be different by default is that DragonFly BSD
apparently has random IP IDs by default (he says from just a brief skim of
some release notes); but since that's available as an option for FreeBSD
too, it doesn't seem like a good way to tell them apart.

-- 
 Colin Phipps
 Netcraft