诊断并解决CentOSSSH连接慢的方法.docx

诊断并解决CentOS SSH连接慢的方法每次PuTTY使用SSH登录到远程的Linux进行管理的时候，远程登录的过程都非常慢——输入完用户名之后，非要等到30秒左右才会出来输入密码的提示。在实际处理问题的时候，特别需要快速响应的时候，这种状况着实让人难以忍受。但后来具体测试了一下，发现这又并非是每种系统的通病，出现问题的机器主要集中的CentOS上，同样的Debian系统，在远程连接的过程就是健步如飞，丝毫没有卡顿犹豫的感觉。这难道是CentOS的问题？出于好奇，查看了下两个系统在SSH时的差别CentOS：ssh -v ssh_test@192.168.128.137SSH远程登录的时候显示的信息如下：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_5.3debug1: match: OpenSSH_5.3 pat OpenSSH_5*debug1: Enabling compatibility mode for protocol 2.0debug1: Local version string SSH-2.0-OpenSSH_6.0p1 Debian-4debug1: SSH2_MSG_KEXINIT sentdebug1: SSH2_MSG_KEXINIT receiveddebug1: kex: server-client aes128-ctr hmac-md5 nonedebug1: kex: client-server aes128-ctr hmac-md5 nonedebug1: SSH2_MSG_KEX_DH_GEX_REQUEST(102410248192) sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_GROUPdebug1: SSH2_MSG_KEX_DH_GEX_INIT sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY...Some sensitive information...debug1: ssh_rsa_verify: signature correctdebug1: SSH2_MSG_NEWKEYS sentdebug1: expecting SSH2_MSG_NEWKEYSdebug1: SSH2_MSG_NEWKEYS receiveddebug1: Roaming not allowed by serverdebug1: SSH2_MSG_SERVICE_REQUEST sentdebug1: SSH2_MSG_SERVICE_ACCEPT receiveddebug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,passworddebug1: Next authentication method: gssapi-keyexdebug1: No valid Key exchange contextdebug1: Next authentication method: gssapi-with-micdebug1: Unspecified GSS failure. Minor code may provide more informationCannot determine realm for numeric host addressdebug1: Unspecified GSS failure. Minor code may provide more informationCannot determine realm for numeric host addressdebug1: Unspecified GSS failure. Minor code may provide more informationdebug1: Unspecified GSS failure. Minor code may provide more informationCannot determine realm for numeric host addressdebug1: Next authentication method: publickeydebug1: Trying private key: /home/mitchellchu/.ssh/id_rsade