[oclug] Netcraft.com uptime

[David F. Skoll]

Hi,

Remember a long time ago I asked how Netcraft can remotely determine
the uptime of a Linux box?

(Try http://uptime.netcraft.com/up/graph?site=www.backstreet.net&display=uptime,
for example.)

I figured out how it's done. Linux sends a "timestamp" option with
some TCP packets.  This timestamp contains the number of jiffies
(hundredths of a second) since the system was booted.

I'm sure it would be a tiny patch to add, oh I don't know, 300 days of
uptime to all the TCP timestamps, so Netcraft suddenly thinks Linux boxes
are extremely reliable. :-)

--
David.