How can I change the ticket lifetime used by Kerberos?

Start the Active Directory Users and Computers MMC snap-in (Start - Programs - Administrative Tools - Active Directory Users and Computers)

Right click on the domain and select Properties from the context menu

Select the 'Group Policy' tab

Select the domain group policy object and click Edit

Expand the Computer Configuration root then Weindows Settings - Security Settings - Kerberos Policy

Double click the time you wish to change, modify and click OK
Click here to view image

Close the group policy editor