[root@server ~]#vim /etc/ssh/sshd_config
........
GSSAPIAuthentication yes
GSSAPICleanupCredentials yes

那么在客户端登录服务端会用gssapi-keyex,gssapi-with-mic进行身份校验,同样客户端也要支持这种身份验证,如下:

[root@client ~]#vim /etc/ssh/ssh_config
GSSAPIAuthentication yes
GSSAPIDelegateCredentials yes

我们在客户端连接SSH服务端,如下:
ssh -v 192.168.1.11
.................
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

我们看到如下的信息:
debug1: Unspecified GSS failure. Minor code may provide more information
No credentials cache found
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
说明SSH登录时采用GSSAPI的方式进行身份验证,但我们的系统不支持.

最后如果我们不用这种方式进行身份验证的话,建议关闭这个选项,这样可以提高验证时的速度.