How to synchronize system time between asterisk и linux?

How can I synchronize system time between asterisk and linux?

The comand date gives me- Wed May 28 09:00:12 EDT 2008

At the same time this line

exten => s,n,GotoIfTime(13:00-21:59,mon-fri,*,*?open) 

works like it is this line-

exten => s,n,GotoIfTime(09:00-17:59,mon-fri,*,*?open) 

In other words I have four hours difference in time between asterisk and linux…

Any idea?

Thanks.
[/code]