RSYNC without password request

[ittcl]

Hello

I have recently purchased 3 x AS-609R, 9 x 4TB, RAID 6.

They seems to work very well, although, I am having some issue to redirect my rsync script toward the main NAS [192.168.1.11]

when i run on the client ;
rsync.exe -ruphtz --stats --delete-after --log-file=/cygdrive/d/tclsys/log/rsync/fullbackupstile.log --exclude "IT" /cygdrive/d/STILE/ rsync@192.168.1.11::stile
I get asked "password:" which is the password of the 'rsync' user that I have defined on the domain, as well as user to access each rsync module on each NAS.

When I enter the password the script runs correctly and I have synced the folder perfectly

Any idea/suggestion on how to avoid entering the password every time?
ssh-keygen? where?
Other methods on the NAS?

Thank You very much in advance

[zurk]

rsync over ssh with ssh key auth