Today I was attempting to back up my in-house CUCM and CXN to a Raspberry Pi which already had SSH enabled.
By Default, when SSH is enabled on Pi, SFTP is enabled as well, using OpenSSH built in to Rasbian.*
I kept getting this error:
admin:utils disaster_recovery device add network berrypi ./ 192.168.41.240 pi 2
Please enter password to connect to network server 192.168.41.240:********
drfCliMsg: Unable to save Backup Device successfully. Update failed : Unable to access SFTP server. Please ensure the username and password are correct.
I did some further research and found that CUCM uses some older Ciphers for SFTP, so I ssh'd in to my Pi and entered the following:
nano /etc/ssh/sshd_config
added the following lines:
#secure ciphers and MAC
ciphers aes128-cbc,3des-cbc,blowfish-cbc,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com
kexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
This resolved the login problems.
*This likely applies to any recent Debian release, including Ubuntu
