SSH客户端(如PuTTY)ssh远程登录Linux非常慢的解决方法

转：http://blog.useasp.net/archive/2014/05/19/solved-the-problem-of-ssh-client-such-as-putty-remote-login-linux-very-slowly.aspx

ssh -v ssh_test@192.168.128.137

SSH远程登录的时候显示的信息如下

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OpenSSH_6.0p1 Debian-4, OpenSSL 1.0.1e 11 Feb 2013

...Some sensitive information...

debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3

debug1: match: OpenSSH_5.3 pat OpenSSH_5*

debug1: Enabling compatibility mode for protocol 2.0

debug1: Local version string SSH-2.0-OpenSSH_6.0p1 Debian-4

debug1: SSH2_MSG_KEXINIT sent

debug1: SSH2_MSG_KEXINIT received

debug1: kex: server->client aes128-ctr hmac-md5 none

debug1: kex: client->server aes128-ctr hmac-md5 none

debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent

debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP

debug1: SSH2_MSG_KEX_DH_GEX_INIT sent

debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY

...Some sensitive information...

debug1: ssh_rsa_verify: signature correct

debug1: SSH2_MSG_NEWKEYS sent

debug1: expecting SSH2_MSG_NEWKEYS

debug1: SSH2_MSG_NEWKEYS received

debug1: Roaming not allowed by server

debug1: SSH2_MSG_SERVICE_REQUEST sent

debug1: SSH2_MSG_SERVICE_ACCEPT received

debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

debug1: Next authentication method: gssapi-keyex

debug1: No valid Key exchange context

debug1: Next authentication method: gssapi-with-mic

debug1: Unspecified GSS failure.  Minor code may provide more information

Cannot determine realm for numeric host address

 debug1: Unspecified GSS failure.  Minor code may provide more information

Cannot determine realm for numeric host address

 debug1: Unspecified GSS failure.  Minor code may provide more information

 debug1: Unspecified GSS failure.  Minor code may provide more information

Cannot determine realm for numeric host address

 debug1: Next authentication method: publickey

debug1: Trying private key: /home/mitchellchu/.ssh/id_rsa

debug1: Trying private key: /home/mitchellchu/.ssh/id_dsa

debug1: Trying private key: /home/mitchellchu/.ssh/id_ecdsa

debug1: Next authentication method: password

从上面可以看到，在CentOS中，系统使用了publickey，gssapi-keyex，gssapi-with-mic，和password来进行认证

下面先放出处理GSSAPI的方法：

禁用GSSAPI认证有两个方式：客户端和服务端

直接配置你ssh客户端的文件/etc/ssh/ssh_config来达到永久解决这个问题：

客户端禁用GSSAPIAuthentication

vi /etc/ssh/ssh_config

修改为GSSAPIAuthentication no

 

服务端禁用GSSAPIAuthentication

vi /etc/ssh/sshd_config

修改为GSSAPIAuthentication no

修改为UseDNS no

 

最后重启SSH服务：service sshd restart