我和我的朋友正试图通过外部网络在他的服务器上获得 ssh 访问权限。他正在运行 Debian 7.1。他可以从内部网络访问服务器，但是每次我尝试访问他的服务器（当然是从外部网络）时，都会出现以下错误。
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/MyUser/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /Users/MyUser/.ssh/id_dsa
debug3: no such identity: /Users/MyUser/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
MyUser@HisServer.com's password:
debug3: packet_send2: adding 64 (len 56 padlen 8 extra_pad 64)
debug2: we sent a password packet, wait for reply
debug1: Authentications that can continue: publickey,password
Permission denied, please try again.
的权限~/.ssh/是 700 和~/.ssh/*600。他有
RSAAuthentication yes
PubkeyAuthentication yes
ChallengeResponseAuthentication yes
PasswordAuthentication no
UsePAM yes
包含在他的sshd_config. 端口检查器说端口 22/tcp 已打开。最奇怪的是，我们在日志中找不到任何访问历史记录。sudo grep ssh /var/log/*只显示他的活动。因此，我怀疑是路由器的配置导致了问题，但是如果端口打开，我们不应该能够 ssh 吗？