SSH login to Cisco switch using public key - protocol error, type 60

Eugene.alekseev — Fri, 21 Feb 2020 14:13:25 GMT

I issued strange problem while trying to connect from Debian system to Cisco C2960 via SSH using public keys.

I generated keys in my Windows XShell client (RSA, 1024bit). After it I exported those key to PEM-format file and send to my remote Debian.

So, for now if I try to connect via SSH using private key from any Windows client (XShell, Putty) - everything is OK.

When I try to connect from my Debian machine - I receive error "Disconnecting: protocol error: rcvd type 60".

Some diagnostic information:

root@debian#ssh -vvv -i key.pem admin@cisco-switch-address:
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 *
debug2: ssh_connect: needpriv 0
debug1: Connecting to cisco-switch-address [10.10.10.10] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: key_load_public: No such file or directory
debug1: identity file key.pem type -1
debug1: key_load_public: No such file or directory
debug1: identity file key.pem-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 Cisco-1.25
debug1: no match: Cisco-1.25
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "cisco-switch-address" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /root/.ssh/known_hosts:5
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-he1
debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-ns
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-e
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-e
debug2: kex_parse_kexinit: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-6
debug2: kex_parse_kexinit: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-6
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: setup hmac-sha1
debug1: kex: server->client aes128-cbc hmac-sha1 none
debug2: mac_setup: setup hmac-sha1
debug1: kex: client->server aes128-cbc hmac-sha1 none
debug2: bits set: 1013/2048
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
debug1: Server host key: RSA d3:19:39:d5:df:3a:09:f8:f5:a1:c2:84:c8:da:f6:9a
debug3: load_hostkeys: loading entries for host "cisco-switch-address" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /root/.ssh/known_hosts:5
debug3: load_hostkeys: loaded 1 keys
debug3: load_hostkeys: loading entries for host "10.10.10.10" from file "/root/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /root/.ssh/known_hosts:6
debug3: load_hostkeys: loaded 1 keys
debug1: Host 'cisco-switch-address' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:5
debug2: bits set: 1045/2048
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: key.pem ((nil)), explicit
debug1: Authentications that can continue: publickey,keyboard-interactive,password
debug3: start over, passed a different list publickey,keyboard-interactive,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: key.pem
debug3: sign_and_send_pubkey: RSA a0:93:b7:5e:9a:e8:ed:4c:34:2b:b1:58:b3:34:ce:b2
debug2: we sent a publickey packet, wait for reply
Disconnecting: protocol error: rcvd type 60

Config updates on Cisco:

username admin privilege 15 secret <password here>
ip ssh pubkey-chain 
username admin
key-string
AAAAB3NzaC1yc2EAAAABIwAAAIEAv69fgC6f9Y3hbxd+IwOmMR
1AYWbEbfb7KCf3O14JK32/DNR5VAa8wq/8yPGajjYXHPXJfwzr
BIjXj2lIQ9iVlj9mGga9nzbQulewJwue2JFuYOydN1phjt5UzG
6e7w+EI/4rzWpllQd40wWDDo2/OKM7++DbQoocMYM1Kg4nogU=
end

I revolve so issue by very

Eugene.alekseev — Wed, 16 Aug 2017 15:03:25 GMT

I revolve that issue by very strange way. I just put public key in format PRIVATE-KEY-FILENAME.pub in the same directory, as private key - and it works now.

For example:

root@debian:~/123# ls -l
total 4
-rw------- 1 root root 891 Aug 16 17:56 newswitch.key
root@debian:~/123# ssh -i newswitch.key admin@<switch-ip-address>
Disconnecting: protocol error: rcvd type 60

After adding public key file:

root@debian:~/123# ls -l
total 8
-rw------- 1 root root 891 Aug 16 17:56 newswitch.key
-rw-r--r-- 1 root root 213 Aug 16 17:57 newswitch.key.pub
root@deb-radius:~/123# ssh -i newswitch.key admin@<switch-ip-address>
<switch-name>#exit
Connection to <switch-ip-address> closed by remote host.
Connection to <switch-ip-address> closed.
root@debian:~/123#

topic I revolve so issue by very in Network Security

SSH login to Cisco switch using public key - protocol error, type 60

I revolve so issue by very