排除SSH主机密钥验证故障

简介

本文档介绍解决SSH主机密钥验证失败问题的过程。

背景

当用户在升级DNACenter映像后尝试通过SSH连接到DNACenter的网关时，会发生此错误。到目前为止，此问题只出现在macOS用户中。

描述

将DNACenter升级到新映像后，本地用户的SSH密钥注册表文件会保留用于连接到以前的DNACenter的梯形内部版本的SSH密钥。这是错误：

MPAVLOVI-M-902T:~ mpavlovi$ ssh grapevine@172.16.21.86 -p 2222
       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
       @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
       @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
       IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
       Someone could be eavesdropping on you right now (man-in-the-middle attack)!
       It is also possible that a host key has just been changed.
       The fingerprint for the ECDSA key sent by the remote host is
       SHA256:+dnn+NRIXTDMmgpUNbeqdjDQscabBBWmC35F01ZFnLs.
       Please contact your system administrator.
       Add correct host key in /Users/mpavlovi/.ssh/known_hosts to get rid of this message.
       Offending ECDSA key in /Users/mpavlovi/.ssh/known_hosts:16
       ECDSA host key for [172.16.21.86]:2222 has changed and you have requested strict checking.
       Host key verification failed.
MPAVLOVI-M-902T:~ mpavlovi$

解决方案

要解决此问题，需要从本地目录~/.ssh/处的注册表文件known_host中删除以前的格雷夫因SSH密钥。

要删除之前的SSH密钥，请转到终端并使用您选择的文本编辑器打开文件：
      

MPAVLOVI-M-902T:~ mpavlovi$ vim ~/.ssh/known_hosts 

继续删除其中包含DNACenter IP地址的行

[10.197.218.12]:2222 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBKkToWAUheuqt876tDOrWwDSH5HbL0TLMw5MAsOsLqCnb3jRn5oxIJn2yECB1HPamglO/m79o2W8mAGAjypyFkw=
[172.16.21.86]:2222 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBKz4ObQLQE7VEHZLOYL0t6k8aqbvFGIFDXsVaTguchsSNyGScFa6PLJKCZj/S7YIultUTYH94NZv4pCl509svvk=

注意：修改其他密钥可能会影响您对其他设备/站点的SSH访问。仅删除必要的SSH密钥。

[10.197.218.12]:2222 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBKkToWAUheuqt876tDOrWwDSH5HbL0TLMw5MAsOsLqCnb3jRn5oxIJn2yECB1HPamglO/m79o2W8mAGAjypyFkw=

将更改保存在文本编辑器中，并重试通过SSH连接到DNACenter grapevine。出现提示时，键入单词“yes”。

MPAVLOVI-M-902T:~ mpavlovi$ ssh grapevine@172.16.21.86 -p 2222 
The authenticity of host '[172.16.21.86]:2222 ([172.16.21.86]:2222)' can't be established.
ECDSA key fingerprint is SHA256:+dnn+NRIXTDMmgpUNbeqdjDQscabBBWmC35F01ZFnLs.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[172.16.21.86]:2222' (ECDSA) to the list of known hosts.

使用grapevine凭据密码。

grapevine@172.16.21.86's password: 

Welcome to the Cisco APIC-EM Appliance - Powered by Grapevine

  System information as of Wed Jul 19 22:20:17 UTC 2017

  System load:  1.02                Users logged in:          1
  Usage of /:   11.7% of 365.80GB   IP address for eth0:      12.99.1.2
  Memory usage: 41%                 IP address for eth1:      172.16.21.86
  Swap usage:   0%                  IP address for grape-br0: 169.254.0.1
  Processes:    695

  APIC-EM Version:   2.0.0.3757
  Grapevine Version: 2.0.0.3757.dev1065-ge50d0c2

Last login: Wed Jul 19 21:45:22 2017 from 10.41.49.41
(grapevine)
[Wed Jul 19 22:20:18 UTC] grapevine@12.99.1.2 (grapevine-root-1) ~
$