Howto setup a desy cross-realm setup

To Setup:


a.) login to desy-computer with desy-login 

b.) aklog -cell physnet.uni-hamburg.de
(optional: bb.) do a klist to see, that you really get a cross-realm ticket)

should look like: 
09/17/19 07:04:13  09/18/19 07:04:13  krbtgt/DESY.DE@DESY.DE

09/17/19 07:04:13  09/18/19 07:04:13  afs/desy.de@DESY.DE

09/17/19 07:04:29  09/18/19 07:04:13  krbtgt/PHYSNET.UNI-HAMBURG.DE@DESY.DE.       <--- NEW

09/17/19 07:04:29  09/18/19 07:04:13  afs/physnet.uni-hamburg.de@                              <--- NEW

09/17/19 07:04:29  09/18/19 07:04:13  afs/physnet.uni-hamburg.de@PHYSNET.UNI-HAMBURG.DE.      <---- NEW


c.) login to physnet-resource with Physnet-login (like login01)
d.) aklog -cell desy.de
(optional dd.) do a klist to see the difference ;-))
(optional ddd.) do a 'ls /afs/desy.de/user/<desy-userdir>/private' to check that is really protected

e.) on the DESY-side:    fs sa private <physnet-user>@PHYSNET.UNI-HAMBURG.DE write 
(optional ee.) check on the Physnet-side if you can read the private folder with ls ...)
f.) on the Physnet-side:        fs sa . <desy-user>@DESY.DE write

[WARNING: you have to Re-Do e.+f. for every existent subfolder you want to be able to use cross-realm] 

To Use later on: 
simply: 
aklog -cell <otherside> 

to have a token in the other cell and be able to access the dirs.