[root@NB Downloads]# ssh -p22022 -vv .5x.xx.xxx

OpenSSH_5.3p1, OpenSSL 1.0.1e-fips  Feb

debug1: Reading configuration data /etc/ssh/ssh_config

debug1: Applying options for *

debug2: ssh_connect: needpriv

debug1: Connecting to .xx.xxx.xx [123.57.xx.xxx] port .

debug1: Connection established.

debug1: permanently_set_uid: /

debug1: identity file /root/.ssh/identity type -

debug1: identity file /root/.ssh/identity-cert type -

debug1: identity file /root/.ssh/id_rsa type -

debug1: identity file /root/.ssh/id_rsa-cert type -

debug1: identity file /root/.ssh/id_dsa type -

debug1: identity file /root/.ssh/id_dsa-cert type -

debug1: identity file /root/.ssh/id_ecdsa type -

debug1: identity file /root/.ssh/id_ecdsa-cert type -

ssh_exchange_identification: Connection closed by remote host

# cat /etc/hosts.allow

#

# hosts.allow    This file contains access rules which are used to

#        allow or deny connections to network services that

#        either use the tcp_wrappers library or that have been

#        started through a tcp_wrappers-enabled xinetd.

#

#        See 'man 5 hosts_options' and 'man 5 hosts_access'

#        for information on rule syntax.

#        See 'man tcpd' for information on tcp_wrappers

#

sshd:all #加上这一行问题解决