求助：OpenBSD更换IP后ssh登录缓慢 ---- 已解决

alittlemoth

解决办法和新的问题在7楼
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vmare下安装的OpenBSD4.8，网络是桥接，固定ip，原先ssh远程登录很快，后更换网络环境，ip更改成另一网段的，ip，网关，dns，hosts都做了相应更改，可ssh登录缓慢，pietty终端连接很快，立马出来login as：，但输入用户后，等待password：出现的时间很长，估计要半分钟？why？还需要更改那些配置？望高人指点

alittlemoth

ssh调试模式登录过程信息如下，就卡在标记那里，很慢，估摸半分钟才能继续，why？

1. # ssh -v 192.168.18.140
   
2. OpenSSH_5.6, OpenSSL 0.9.8k 25 Mar 2009
   
3. debug1: Reading configuration data /etc/ssh/ssh_config
   
4. debug1: Connecting to 192.168.18.140 [192.168.18.140] port 22.
   
5. debug1: Connection established.
   
6. debug1: permanently_set_uid: 0/0
   
7. debug1: identity file /root/.ssh/id_rsa type -1
   
8. debug1: identity file /root/.ssh/id_rsa-cert type -1
   
9. debug1: identity file /root/.ssh/id_dsa type -1
   
10. debug1: identity file /root/.ssh/id_dsa-cert type -1
    
11. debug1: Remote protocol version 2.0, remote software version OpenSSH_5.6
    
12. debug1: match: OpenSSH_5.6 pat OpenSSH*
    
13. debug1: Enabling compatibility mode for protocol 2.0
    
14. debug1: Local version string SSH-2.0-OpenSSH_5.6
    
15. debug1: SSH2_MSG_KEXINIT sent
    
16. debug1: SSH2_MSG_KEXINIT received
    
17. debug1: kex: server->client aes128-ctr hmac-md5 none
    
18. debug1: kex: client->server aes128-ctr hmac-md5 none
    
19. debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
    
20. debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
    
21. debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
    
22. debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
    
23. debug1: Host '192.168.18.140' is known and matches the RSA host key.
    
24. debug1: Found key in /root/.ssh/known_hosts:1
    
25. debug1: ssh_rsa_verify: signature correct
    
26. debug1: SSH2_MSG_NEWKEYS sent
    
27. debug1: expecting SSH2_MSG_NEWKEYS
    
28. debug1: SSH2_MSG_NEWKEYS received
    
29. debug1: Roaming not allowed by server
    
30. debug1: SSH2_MSG_SERVICE_REQUEST sent
    
31. debug1: SSH2_MSG_SERVICE_ACCEPT received      <<=====卡在这里
    
32. debug1: Authentications that can continue: publickey,password,keyboard-interactive
    
33. debug1: Next authentication method: publickey
    
34. debug1: Trying private key: /root/.ssh/id_rsa
    
35. debug1: Trying private key: /root/.ssh/id_dsa
    
36. debug1: Next authentication method: keyboard-interactive
    
37. debug1: Authentications that can continue: publickey,password,keyboard-interactive
    
38. debug1: Next authentication method: password
    
39. root@192.168.18.140's password:
    

复制代码

xiaoshi20cn

改一下密钥？

猴马大叶

Roaming not allowed by server
这句啥意思?


好像是你验证不成功...然后系统换了一种方式让你继续登录.

alittlemoth

更换密钥后还是无效。

Roaming not allowed by server
应该是服务器不允许漫游吧。

我本来就用的是需要口令登录，虽然登录慢，但大约半分钟后出现提示输入密码时，一旦密码输入后就登录正常了，而且操作也正常，奇怪的来。

sopato

是不是要清空一下.ssh的公钥文件啊，另外hosts表中加进新IP试试。

alittlemoth

问题是找到了，DNS的问题，只要禁用ssh的DNS就行了，不过比较奇怪，我的机子在内网，默认网关是192.168.18.1，而我们这的电信DNS是61.177.7.1，只要把openbsd的dns改成电信的DNS地址就算ssh使用DNS也能迅速登录，而把DNS设为192.168.18.1就登录缓慢，难道路由器默认不转发DNS请求？？？？


特地在虚拟机下有安装了一个全新的openbsd系统，安装过程中dns设为路由器的地址：192.168.18.1，ssh登录果然还是缓慢，看样子是DNS的问题，但是在系统下ping外网网站的域名又能通，这么说路由器的DNS转发和域名解析也没问题，为啥就是ssh会有问题呢？百思不得其解，hosts文件也设置正常，回环，本机地址一个不差，奇怪的来{:3_201:}

congli

试一下
/etc/ssh/sshd_config
UseDNS no

alittlemoth

回复 8# congli


    这个办法确实是可以，但我就是没明白，如果我把DNS直接设为WAN的DNS地址（就是咱们这边的电信DNS）就能正常迅速登录，哪怕是UseDNS yes，但一旦我把DNS设为网关地址，靠网关转发DNS，同时UseDNS yes登录就很慢，而网关DNS转发功能又没问题

bestwc

我做服务器第一件事情就是禁用DNS

ee /etc/ssh/sshd_config
-------------------------------------
UseDNS no
-------------------------------------
/etc/rc.d/sshd forcerestart