Not all tickets are alike. One ticket might be, for example, forwardable; another ticket might be postdated; while a third ticket might be both forwardable and postdated. You can see which tickets you have, and what their attributes are, by using the klist command with the -f option:
| % /usr/bin/klist -f | 
The following symbols indicate the attributes that are associated with each ticket, as displayed by klist:
| F | Forwardable | 
| f | Forwarded | 
| P | Proxiable | 
| p | Proxy | 
| D | Postdateable | 
| d | Postdated | 
| R | Renewable | 
| I | Initial | 
| i | Invalid | 
Types of Tickets describes the various attributes that a ticket can have.
This example shows that the user jennifer has an initial ticket, which is forwardable (F) and postdated (d), but not yet validated (i):
| % /usr/bin/klist -f
Ticket cache: /tmp/krb5cc_74287
Default principal: jenniferm@ENG.EXAMPLE.COM
 
Valid starting                 Expires                 Service principal
09 Mar 99 15:09:51  09 Mar 99 21:09:51  nfs/EXAMPLE.SUN.COM@EXAMPLE.SUN.COM
        renew until 10 Mar 99 15:12:51, Flags: Fdi
  | 
The following example shows that the user david has two tickets that were forwarded (f) to his host from another host. The tickets are also forwardable (F):
| % klist -f
Ticket cache: /tmp/krb5cc_74287
Default principal: david@EXAMPLE.SUN.COM
 
Valid starting                 Expires                 Service principal
07 Mar 99 06:09:51  09 Mar 99 23:33:51  host/EXAMPLE.COM@EXAMPLE.COM
        renew until 10 Mar 99 17:09:51, Flags: fF
 
Valid starting                 Expires                 Service principal
08 Mar 99 08:09:51  09 Mar 99 12:54:51  nfs/EXAMPLE.COM@EXAMPLE.COM
        renew until 10 Mar 99 15:22:51, Flags: fF |