For example there are two servers hosta and hostb
to enable passwordless scp from hosta to hostb do the followings,
a. login to hosta server and from the home directory go to .ssh/ directory
b. open and copy the content of the file "id_dsa.pub"
c. Login to the hostb server(navigate to .ssh/ directory ) and paste the content copied from hosta server to the file "authorized_keys" in the hostb server.
d. try the copy process
Note : - if .ssh directory is missing in the server create it using "ss h-keygen -t dsa" command, this would create the .ssh directory in the home location.Then proceed with step a, b,c and d.