ssh in debug mode

1.Use command to ligin debug mode with ssh server
#/usr/sbin/sshd -d
notice the sshd must be absolute path
it will show
debug1: sshd version......
debug1: read PEM Private key done.......
debug1: Checking blacklist file /usr/share/ssh.......
debug1: Checking blacklist file /etc/ssh/blacklist.......
debug1: private host key: #0 type 1 Rsa.....