这两天ssh登录局域网的一台服务器非常慢，严重影响工作效率，怎么办？查了一下网上的解决办法，总结一下：
使用命令ssh -v xxx@x.x.x.x
可以看到debug信息，找到问题出在哪：
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
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/szyl/.ssh/identity
debug1: Trying private key: /home/szyl/.ssh/id_rsa
debug1: Trying private key: /home/szyl/.ssh/id_dsa
debug1: Next authentication method: password
发现一直卡在gssapi-with-mic这步，解决方法：
打开(远程服务器) /etc/ssh/sshd_config（注意是文件 /etc/ssh/sshd_config 而不是/etc/ssh/ssh_config），
1、把里面的 GSSAPIAuthentication yes 改成 no；
2、把里面的UseDNS yes 改成 no；
3、/etc/init.d/sshd restart 重启sshd进程使配置生效。
netstat -a | more 看有没正常启动，如果出现：
tcp 0 0 *:ssh *:* LISTEN
就说明正常启动了。
大功告成！处理前后建立 ssh 连接时间的对比:
$ time xxx@x.x.x.x
real 0m53.129s
user 0m0.005s
sys 0m0.007s
$ time xxx@x.x.x.x
real 0m1.122s
user 0m0.005s
sys 0m0.004s
so fast！如没能解决你的问题，请参照这篇：http://linux.chinaunix.net/techdoc/net/2008/08/06/1023398.shtml