ssh 連接慢解決辦法

現象：在區域網內，能ping通目標機器，並且時延是微秒級。

用ssh連區域網內其他linux機器，會等待10-30秒才有提示輸入密碼。嚴重影響工作效率。

CentOS修改後效果一樣

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客戶端操作系統版本：

cat /etc/lsb-release

DISTRIB_ID=Ubuntu

DISTRIB_RELEASE=9.10

DISTRIB_CODENAME=karmic

DISTRIB_DESCRIPTION="Ubuntu 9.10"0

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調試信息：

[root@IBM ~]# ssh -v 10.10.10.100

OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003

debug1: Reading configuration data /etc/ssh/ssh_config

debug1: Applying options for *

debug1: Connecting to 10.10.10.100 [10.10.10.100] port 22.

debug1: connect to address 10.10.10.100 port 22: Connection refused

ssh: connect to host 10.10.10.100 port 22: Connection refused

----------------[網路上的調試信息]----------------------

ssh -v 192.168.12.16 

OpenSSH_5.1p1 Debian-6ubuntu2, OpenSSL 0.9.8g 19 Oct 2007 

debug1: Reading configuration data /etc/ssh/ssh_config 

debug1: Applying options for * 

debug1: Connecting to 192.168.12.16 [192.168.12.16] port 22. 

debug1: Connection established. 

debug1: identity file /home/zhouhh/.ssh/identity type -1 

debug1: identity file /home/zhouhh/.ssh/id_rsa type -1 

debug1: identity file /home/zhouhh/.ssh/id_dsa type -1 

debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3 

debug1: match: OpenSSH_4.3 pat OpenSSH_4* 

debug1: Enabling compatibility mode for protocol 2.0 

debug1: Local version string SSH-2.0-OpenSSH_5.1p1 Debian-6ubuntu2 

debug1: SSH2_MSG_KEXINIT sent 

debug1: SSH2_MSG_KEXINIT received 

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

debug1: kex: client->server aes128-cbc 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 

debug1: Host '192.168.12.16' is known and matches the RSA host key. 

debug1: Found key in /home/zhouhh/.ssh/known_hosts:1 

debug1: ssh_rsa_verify: signature correct 

debug1: SSH2_MSG_NEWKEYS sent 

debug1: expecting SSH2_MSG_NEWKEYS 

debug1: SSH2_MSG_NEWKEYS received 

debug1: SSH2_MSG_SERVICE_REQUEST sent 

debug1: SSH2_MSG_SERVICE_ACCEPT received 

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

debug1: Next authentication method: gssapi-with-mic 

debug1: An invalid name was supplied 

Cannot determine realm for numeric host address 

debug1: An invalid name was supplied 

Cannot determine realm for numeric host address 

debug1: An invalid name was supplied 

debug1: Next authentication method: publickey 

debug1: Trying private key: /home/zhouhh/.ssh/identity 

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

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

debug1: Next authentication method: password 

password:   

debug1: Authentication succeeded (password). 

debug1: channel 0: new [client-session] 

debug1: Entering interactive session. 

debug1: Sending environment. 

debug1: Sending env LANG = zh_CN.UTF-8 

Last login: Fri Dec 25 13:35:04 2009 from 192.168.11.146 

可以看到如下的錯誤信息：

debug1: Next authentication method: gssapi-with-mic

debug1: An invalid name was supplied

Cannot determine realm for numeric host address

事實上，正是從gssapi-with-mic這一行開始，開始耗時間。