vim /etc/ssh/sshd_config
加入這一行,并重啟ssh服務(wù):
KexAlgorithms curve25519-sha256,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
原因:老版crt和ubuntu20.4加密算法不匹配