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Hello.
When you want SSH to a new server for the first time, SSH show you a key that must be adding to "known_hosts" file but if I want to remove a specific SSH key server then how can I find it?
For example, When I SSH to a server an output like below shown :
Code:
OpenSSH_6.7p1 Debian-5+deb8u3, OpenSSL 1.0.1t 3 May 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to Server [IP] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/jason/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.7p1 Debian-5+deb8u3
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr umac-64@openssh.com zlib@openssh.com
debug1: kex: client->server aes128-ctr umac-64@openssh.com zlib@openssh.com
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<3072<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA 9a:91:c9:92:05:5d:df:8d:47:b7:fc:4c:17:51:64:1d
debug1: Host 'usa-1.createssh.com' is known and matches the RSA host key.
debug1: Found key in /home/jason/.ssh/known_hosts:33
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available
debug1: Unspecified GSS failure. Minor code may provide more information
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available
debug1: Next authentication method: publickey
debug1: Trying private key: /home/jason/.ssh/id_rsa
debug1: Trying private key: /home/jason/.ssh/id_dsa
debug1: Trying private key: /home/jason/.ssh/id_ecdsa
debug1: Trying private key: /home/jason/.ssh/id_ed25519
debug1: Next authentication method: password
jason@Server's password:
debug1: Enabling compression at level 6.
debug1: Authentication succeeded (password).
I know the is in line 33 as output said but when I grep "RSA 9a:91:c9:92:05:5d:df:8d:47:b7:fc:4c:17:51:64:1d" then I can't find anything!!!
Hello.
When you want SSH to a new server for the first time, SSH show you a key that must be adding to "known_hosts" file but if I want to remove a specific SSH key server then how can I find it?
You'll have to hunt for it by host name or ip number and remove the line from known_hosts. If you don't want to dig through known_hosts with an editor, you can have ssh-keygen remove the key for you:
Code:
ssh-keygen -R 198.51.100.13 -f ~/.ssh/known_hosts
That will remove the key and save a backup copy of it in known_hosts.old. That method works even for lists where the host name or ip number is hashed.
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Find a remove an SSH key.
