Fwd: Re: [Samba] clock skew again

Mac mac at nibsc.ac.uk
Thu May 27 12:50:05 GMT 2004

Hi there,

	And thank you for your info.  Most useful.

The problem is that the time is WRONG on one of your machines.

Let me explain how.

> C:\Documents and Settings\rr> echo. |time
> The current time is: 16:14:53.89
> Enter the new time:

Your PC thinks it is 16:14  this is fine.


So your PC is in a TimeZone 5 hours ahead of GMT. This 
too is fine (assuming you're somewhere in Pakistan)

Note that this means that the GMT time (according to 
your PC) is:-

	16:14 - 5   =  11:14  GMT

>[root at niit125 root]# date
>Thu May 27 16:22:21 PKST 2004

So your Linux box thinks it's 16:22 and it is in timezone
PKST (Pakistan Summer Time)

>[root at niit125 root]# date -u
>Thu May 27 10:22:23 UTC 2004

And your Linux box can also give you the time in GMT directly. (I had
to calulate it for your PC)

It thinks it is 10:22 UTC whihc is 10:22 GMT  (UTC is just the new and
official name for GMT)

Now you can see the problem.

Kerberos (because it has to work across the whole world) always uses GMT
for its time.  GMT is the same across the whole world and does not
have any 'Summer Time' variations.  

In fact, all decent computer systems use only GMT for talking to _each_

They still tell _you_ the local time, taking into account what time zone you're
in, but they all talk to each other with GMT.

I can tell from the time you sent the messages, that the Linux box's time is

It should have been 11:22 UTC.

You can set this by using 'date -u 1122' (or whatever the correct GMT time is)

What this means is that the Linux box's timezone setting is wrong too, because
when you set the GMT time on the Linux box to the right time, the Time Zone
of PKST would show 17:22.


To get your Kerberos to work, you need to set both clocks to the same GMT time.

I think your PC is right 16:22 +5hrs is equivalent to 11:22 GMT

I think your Linux box is wrong because it says 10:22 UTC  which is 10:22 GMT.

Set the time forward by an hour on your Linux box and I'll bet the 'clock-skew'
error message will go away.

You'll then have to figure out the correct TimeZone setting for your
Linux box but you need to get the GMT (UTC) time right first.

There's loads of places you check current GMT (UTC) time here's one:-


          Assistant Systems Adminstrator @nibsc.ac.uk
                        dmccann at nibsc.ac.uk
   Work: +44 1707 641565          Everything else: +44 7956 237670 (anytime)

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