linux下SSH远程连接服务慢解决方案

linux下SSH远程连接服务慢解决方案

1、适用命令及方案如下：
【远程连接及执行命令】
ssh -p22 root@10.0.0.19
ssh -p22 root@10.0.0.19 /sbin/ifconfig
【远程拷贝：推送及拉取】
scp -P22 -r -p /etc root@10.0.0.19:/tmp/
scp -P22 -r -p root@10.0.0.19:/tmp/ /etc
【安全的FTP功能】
sftp -oPort=22 root@10.0.0.19
【无密码验证方案】
例如利用sshkey批量分发文件，执行部署操作。

2、连接慢的主要原因是DNS解析导致
解决方法：

1、在ssh服务端上更改/etc/ssh/sshd_config文件中的配置为如下内容：

UseDNS no# GSSAPI optionsGSSAPIAuthentication no然后，执行/etc/init.d/sshd restart重启sshd进程使上述配置生效，在连接一般就不慢了。2、如果还慢的话，检查ssh服务端上/etc/hosts文件中，127.0.0.1对应的主机名是否和uname -n的结果一样，或者把本机ip和hostname(uname -n结果)加入到/etc/hosts里。12345678[root@C64 ~]# uname -nC64[root@C64 ~]# cat /etc/hosts#modi by oldboy 11:12 2013/9/24127.0.0.1   C64 localhost localhost.localdomain localhost4 localhost4.localdomain4::1         localhost localhost.localdomain localhost6 localhost6.localdomain610.0.0.18   C64################3、利用ssh-v的调试功能查找慢的原因其实可以用下面的命令调试为什么慢的细节（学习这个思路很重要）。[root@C64 ~]# ssh -v root@10.0.0.19OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010debug1: Reading configuration data /etc/ssh/ssh_configdebug1: Applying options for *debug1: Connecting to 10.0.0.19 [10.0.0.19] port 22.debug1: Connection established.debug1: permanently_set_uid: 0/0debug1: identity file /root/.ssh/identity type -1debug1: identity file /root/.ssh/id_rsa type -1debug1: identity file /root/.ssh/id_dsa type -1debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3debug1: match: OpenSSH_4.3 pat OpenSSH_4*debug1: Enabling compatibility mode for protocol 2.0debug1: Local version string SSH-2.0-OpenSSH_5.3debug1: 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(1024<1024<8192) sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_GROUPdebug1: SSH2_MSG_KEX_DH_GEX_INIT sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_REPLYThe authenticity of host '10.0.0.19 (10.0.0.19)' can't be established.RSA key fingerprint is ca:18:42:76:0e:5a:1c:7d:ef:fc:24:75:80:11:ad:f9.Are you sure you want to continue connecting (yes/no)? yes=======>这里就是提示保存密钥的交互提示。Warning: Permanently added '10.0.0.19' (RSA) to the list of known hosts.debug1: ssh_rsa_verify: signature correctdebug1: SSH2_MSG_NEWKEYS sentdebug1: expecting SSH2_MSG_NEWKEYSdebug1: SSH2_MSG_NEWKEYS receiveddebug1: SSH2_MSG_SERVICE_REQUEST sentdebug1: SSH2_MSG_SERVICE_ACCEPT receiveddebug1: Authentications that can continue: publickey,passworddebug1: Next authentication method: publickeydebug1: Trying private key: /root/.ssh/identitydebug1: Trying private key: /root/.ssh/id_rsadebug1: Trying private key: /root/.ssh/id_dsadebug1: Next authentication method: passwordroot@10.0.0.19's password:=======>这里就是提示输入密码的交互提示。debug1: Authentication succeeded (password).debug1: channel 0: new [client-session]debug1: Entering interactive session.debug1: Sending environment.debug1: Sending env LANG = en_US.UTF-8Last login: Tue Sep 24 10:30:02 2013 from 10.0.0.18在远程连接时如果慢就可以确定卡在哪了。[root@C64_A ~]# ssh -v oldboy@10.0.0.17OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010debug1: Reading configuration data /etc/ssh/ssh_configdebug1: Applying options for *debug1: Connecting to 10.0.0.17 [10.0.0.17] port 22.debug1: Connection established.debug1: permanently_set_uid: 0/0debug1: identity file /root/.ssh/identity type -1debug1: identity file /root/.ssh/id_rsa type -1debug1: identity file /root/.ssh/id_dsa type 2debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3debug1: match: OpenSSH_5.3 pat OpenSSH*debug1: Enabling compatibility mode for protocol 2.0debug1: Local version string SSH-2.0-OpenSSH_5.3debug1: 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(1024<1024<8192) sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_GROUPdebug1: SSH2_MSG_KEX_DH_GEX_INIT sentdebug1: expecting SSH2_MSG_KEX_DH_GEX_REPLYdebug1: Host '10.0.0.17' is known and matches the RSA host key.debug1: Found key in /root/.ssh/known_hosts:2debug1: ssh_rsa_verify: signature correctdebug1: SSH2_MSG_NEWKEYS sentdebug1: expecting SSH2_MSG_NEWKEYSdebug1: SSH2_MSG_NEWKEYS receiveddebug1: 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-mic

上述配置没配就发现卡到gssapi这。就大概知道是gssapi的问题。
实际上在linux系统优化部分就应该优化SSH服务的此处。