If you log on to your computer by using a smart card, you
may receive a prompt to refresh your credentials if you remain logged on for a
long time.
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Background
When a user logs on using a smart card, Kerberos grants the user
a ticket granting ticket (TGT). With the TGT, the user can acquire tickets to
access other resources on the network without typing any credentials. The TGT
lasts for a fixed amount of time. At the end of this lifetime, the user must
refresh it. To do so, the user must supply credentials by logging on. When you
log on, the TGT is automatically updated. When Windows determines that the user
has an expired TGT, an icon and a message appear on the taskbar of the user's
computer. The message informs the user to update their credentials. TGT Refresh
The TGT has a default lifetime of 10 hours. If a user is logged
on for more than 10 hours, the TGT expires and the user must refresh the TGT.
If the smart card is in the reader, the TGT is refreshed. If the smart card is
not in the reader, the TGT is not refreshed and all later attempts to access
the network fail. To work around this behavior, the user must log off, and then
log on to the computer to get a new TGT. TGT Renewal in Windows XP and Windows 2000 SP2 and Later
By default, the TGT has a default lifetime of 10 hours, but the
user can renew it for up to 7 days. The renewal does not require credentials.
The renewal occurs only if the user uses the TGT within 5 minutes of its
expiration. Otherwise the TGT expires and the user must refresh it (which
requires credentials). TGT Renewal in Windows Server 2003
By default, the TGT has a default lifetime of 10 hours, but the
user can renew it for up to 7 days. The renewal does not require credentials.
The renewal occurs by using a scavenger thread on the computer. If the user
cannot renew the TGT, it expires and the user must refresh it (which requires
credentials). Cached Credentials
If the user logs on with cached credentials, the user cannot
refresh the TGT by unlocking (even without cached credentials, unlocking does
not reliably refresh the TGT on Windows 2000). Otherwise, the user can refresh
the TGT by unlocking and by re-inserting the card.
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