[Samba] Samba 4 - disconnection after 10 hours (Solved)

[X-Dimension]

Am 10.03.2014 17:38, schrieb X-Dimension:
> Am 08.03.2014 13:27, schrieb X-Dimension:
>> Am 27.02.2014 21:08, schrieb X-Dimension:
>>> We have a strange problem since we are using Samba 4.
>>> On our domain controller (Samba 4.1.4) we have a share called 
>>> "programs" where we have installed
>>> all programs that our employees need.
>>> When a domain user (Windows 7 client) is connected round about 10 
>>> hours  to our Samba DC,
>>> all open programs that are installed on the "programs" share seems 
>>> to get lost the connection to
>>> the server and so they crash. We can only close these applications 
>>> by killing them with the Windows task manager.
>>> After this we can start all of these programs without a problem and 
>>> there are working fine again.
>>> It looks like Samba kills the connection after 10 hours although the 
>>> programs are still in use.
>>>
>>> Does anybody has the same problem, or knows what goes wrong here?
>>>
>>> Thx for help!
>>
>> I wonder if nobody else seems to have this problem.
>> I can reproduce this every time here, even after updating to Samba 4.1.5
>>
>> Steps to reproduce are:
>>
>> 1. Install Samba 4 as Active Directory Domain Controller
>> 2. Create a share (call it "Programs" for example)
>> 3. Join the domain with a Windows 7 client and install some programs 
>> to the "Programs" share
>> 4. Open some of these programs on the Windows 7 client computer
>> -> smbstatus on the Samba server should now show many open files for 
>> these programs
>> 5. Leave the programs open on the Windows client and wait around 9 
>> till 10 hours
>> 6. After 9 till 10 hours run smbstatus again on the Samba server and 
>> it shows no open files anymore
>> and all the open programs on the Windows client should not work or 
>> crash now when you click on a menu item
>> in it or something like that.
>>
>> Can anybody confirm this?
>>
>> Thx
> I have done a few tests over the weekend and the disconnection always 
> occurs exactly after 10 hours!
> So i searched for SMB/CIFS timeouts on Google and found that the 
> Kerberos ticket timeout is
> also 10 hours by default.
>
> Is it possible that the Kerberos ticket timeout is the reason for my 
> disconnection problem?
> Maybe there is a problem with Kerberos ticket renewal on the client or 
> server side?
>
> I also found this bug, that sounds similar
> https://bugzilla.samba.org/show_bug.cgi?id=9098#c4
>
> How can i check if Kerberos ticket renewal works on our system or not?
>
> Thx
>
I solved my problem now and the default Kerberos ticket lifetime was 
indeed the reason for the disconnection after 10 hours!

The Samba wiki helped me a lot: 
https://wiki.samba.org/index.php/Samba_KDC_Settings

After adding these lines to smb.conf everything works fine now:

kdc:service ticket lifetime = 24
kdc:user ticket lifetime = 24
kdc:renewal lifetime = 120

But i have still one question. Why does our Windows 7 clients don't 
renew the tickets automatically
before the ticket lifetime exceeds?