Cisco ir829 - No matching kex algorithm found

[Jon Are Endrerud]

Hello

Trying to pickup files with scp from Cisco I829 with fw (ir800-universalk9-mz.SPA.159-3.M2a).

R241#show ip ssh 
SSH Enabled - version 2.0
Authentication methods:publickey,keyboard-interactive,password
Authentication Publickey Algorithms:x509v3-ssh-rsa,ssh-rsa
Hostkey Algorithms:x509v3-ssh-rsa,ssh-rsa
Encryption Algorithms:aes128-ctr,aes192-ctr,aes256-ctr
MAC Algorithms:hmac-sha2-256,hmac-sha2-512,hmac-sha1,hmac-sha1-96
KEX Algorithms:diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1
Authentication timeout: 120 secs; Authentication retries: 3
Minimum expected Diffie Hellman key size : 2048 bits

To a ubuntu host with defined algorithms:

diffie-hellman-group1-sha1
diffie-hellman-group14-sha1
diffie-hellman-group14-sha256
diffie-hellman-group16-sha512
diffie-hellman-group18-sha512
diffie-hellman-group-exchange-sha1
diffie-hellman-group-exchange-sha256
ecdh-sha2-nistp256
ecdh-sha2-nistp384
ecdh-sha2-nistp521
curve25519-sha256
curve25519-sha256@libssh.org
sntrup4591761x25519-sha512@tinyssh.org

I get:

%SSH-3-NO_MATCH: No matching kex algorithm found: client diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1 server curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256

Can anyone help me with this problem ?

SSH from the ubuntu to router gives the same error.

Regards 

Jon

[Giuseppe Larosa]

Hello Jon,

I think you need to modify the configuration file of sshd process on the Ubuntu box to add some algorithms supported by the Cisco IR829 router. Look for documentation in Ubuntu to find where the config file is and edit it and restart sshd process.

Hope to help

Giuseppe

[Jon Are Endrerud]

Have tried this, and as far as I can see they match up. Using the same algoritm with SecureCRT. Will check with linux community.

Thank you.