Iptables, timestart and timestop arguments and daylight saving time in UK

[Sebastian Arcus <shop@open-t.co.uk>]

Hi all,

The clock changed over the weekend in the UK by one hour (daylight 
saving time). I a setup where I block some MAC addresses access to the 
Internet based on time, using iptables, "timestart" and "timestop" 
arguments. The command is the following:

iptables -A FORWARD -p ALL -o eth0 -m mac  --mac-source  $BLOCKED_MAC1 \
    -m time --timestart 13:00 --timestop 12:00 -j DROP


After the weekend, the server kept on blocking as per the old winter 
time. I checked the server time with the "date" command and the time on 
the client machine (Windows XP) - and in both places the clock is 
updated as per new time / summer time. The iptables on server kept on 
blocking according to winter time for two days. Even restarting the 
iptables script (which flushes the tables) didn't make a different. 
Finally, when I restarted the whole server, it started blocking 
according to new summer time. Here is the setup:

Client: Windows XP Home
Server: Slackware 13.0
Kernel: 2.6.29.6
Iptables: 1.4.3.2

Is this a known bug in the kernel, or am I doing something wrong?

Thanks for any contributions,

Sebastian