Warning: remote host identification has changed

[AndreaCogliati]

Core Shell doesn’t let me connect to a host anymore with the message “WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!” I’m sure that I’m connecting to the correct host. How do I remove the old key so I can connect?

[yang (Yang.Y)]

The remote side might has changed its identity, could you please set log level to Debug3 and paste the log here?

Enable logging

The default logging level is set to Info, Debug1, Debug2 and Debug3 each specify higher levels of verbose output. [image] Core Shell Open or go to Hosts tab, right click on the host and select Edit Settings… from context menu, navigate to Connection tab, then scroll down to Log Level option. Press ⌘ I (or select Shell -> Show Inspector from main menu) reveals shell session information, as well as log content. [image] Core Tunnel Navigate to tunnel's Settings…, Connection tab, then scrol…

[AndreaCogliati]

It's possible that the computer is using the same IP address of an older host. Here's the log (I anonymized hostnames and IP addresses):

09:13:47 ----------------------------------------
09:13:47 Equivalent Command: ssh -tt -F "/Users/andreac/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/config" -vvv -o ServerAliveInterval=15 -o ConnectTimeout=15 -o CheckHostIP=yes -o ServerAliveCountMax=3 -o ExitOnForwardFailure=yes -p 82 andreac@curiosity..com
09:13:47 Connecting…
09:13:47 OpenSSH_7.9p1, OpenSSL 1.0.2q 20 Nov 2018
09:13:47 debug1: Reading configuration data /Users/andreac/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/config
09:13:47 debug1: /Users/andreac/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/config line 7: Applying options for *
09:13:47 debug2: resolving "curiosity..com" port 8122
09:13:47 debug2: ssh_connect_direct
09:13:47 debug1: Connecting to curiosity..com [64..*.46] port **22.
09:13:47 debug2: fd 5 setting O_NONBLOCK
09:13:47 debug1: fd 5 clearing O_NONBLOCK
09:13:47 debug1: Connection established.
09:13:47 debug3: timeout: 14983 ms remain after connect
09:13:47 load pubkey "/Users/andreac/.ssh/id_rsa": Operation not permitted
09:13:47 debug1: identity file /Users/andreac/.ssh/id_rsa type -1
09:13:47 debug1: identity file /Users/andreac/.ssh/id_rsa-cert type -1
09:13:47 debug1: identity file /Users/andreac/.ssh/id_dsa type -1
09:13:47 debug1: identity file /Users/andreac/.ssh/id_dsa-cert type -1
09:13:47 debug1: identity file /Users/andreac/.ssh/id_ecdsa type -1
09:13:47 debug1: identity file /Users/andreac/.ssh/id_ecdsa-cert type -1
09:13:48 debug1: identity file /Users/andreac/.ssh/id_ed25519 type -1
09:13:48 debug1: identity file /Users/andreac/.ssh/id_ed25519-cert type -1
09:13:48 Abnormal Disconnect

[yang (Yang.Y)]

Could you please enable system default ssh_config and known_hosts` configurations and try again?

Use system default `ssh_config` and `known_hosts` configuration

By default, Core Tunnel uses configuration files in its own container folder: # known_hosts ~/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/known_hosts # ssh_config ~/Library/Group Containers/E78WKS7W4U.io.coressh.ssh/.ssh/config This works very well in most of cases. But if you have a lengthy ~/.ssh/config or /etc/ssh/ssh_config, or have StrictHostKeyChecking set to yes and use ~/.ssh/known_hosts, /etc/ssh/ssh_known_hosts as the only source data trusted host keys, you may want to u…

If you still not in luck, please execute the command in terminal and send back the output:

ssh -vvv -o CheckHostIP=yes -p 8122 **@curiosity.**.com

[AndreaCogliati]

I just removed the host entry from the know_hosts file, and now I can connect again. Thanks for pointing me in the right direction.

[AndreaCogliati]

BTW, I seem to remember that SSH Shell would just display a warning but let me proceed in the same circumstance. Is it possible to configure Core Shell to do the same?

[yang (Yang.Y)]

It depends, if both host ip and identity were changed, Core Shell would consider it’s not safe to accept the key and continue connecting.