排除SSH主機金鑰驗證失敗故障

簡介

本文檔介紹修復SSH主機金鑰驗證失敗問題的過程。

背景

在升級DNACenter映像後，當使用者嘗試透過SSH連線到DNACenter的網關時，會發生此錯誤。到目前為止，此問題只出現在macOS使用者中。

說明

將DNACenter升級到新映像後，本地使用者的SSH金鑰登錄檔檔案維護用於連線到先前DNACenter的梯形內部版本的SSH金鑰。錯誤如下：

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$

解決方案

要解決此問題，需要從本地目錄~/.ssh/處的登錄檔檔案known_host中刪除之前的梯形SSH金鑰。

要刪除以前的SSH金鑰，請轉到terminal並使用您選擇的文本編輯器打開檔案：
      

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

繼續刪除其中包含DNAC輸入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：修改其他金鑰可能會影響您對其他裝置/站點的SSH訪問。僅刪除所需的SSH金鑰。

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

在文本編輯器中儲存更改，並重試到SSH到DNACenter grapevine。提示時輸入「yes」字樣。

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.

使用葛雷普韋認證密碼。

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) ~
$