Faced this while running installer for setting up a 2 node RAC setup (version 19.8) on an Oracle SuperCluster. The error reported in the log is:
[FATAL] [INS-44000] Passwordless SSH connectivity is not setup from the local node node1 to the following nodes:
[node2]
[INS-06006] Passwordless SSH connectivity not set up between the following node(s): [node2]
From the error it appears that the ssh is not setup between two nodes but actually that is not the case. Here the error message is bi t misleading. It turned out to be an issue with scp with openssh version 8.x. Running the setup with -debug option gives the clue:
<protocol error: filename does not match request>
The reason is a new check introduced in openssh version 8.x. It is explained [here](https://askubuntu.com/questions/1126612/how-to-us e-scp-to-transfer-files-between-ubuntu-and-windows10), [here](https://stackoverflow.com/questions/54598689/scp-fails-with-protocol-er ror-filename-does-not-match-request/54599326#54599326) and here. MOS note 2555697.1 also t alks about it.
Workaround is to pass the -T option to scp to ignore the new checks. You can rename the scp binary to something like scp.original and create a new shell script there like this:
cd /usr/bin
mv scp scp.original
vi scp
/usr/bin/scp.original -T $*
chmod 555 scp
This time, the install should succeed. You can revert the changes back once the install is done.