Open SSH

[moman62]

Hello,

I wanted to know if I'm using Linux, could I access a cisco appliance (router, switch) using Open SSH?

[johnd2310]

Hi,

yes, you can use the open ssh client in Linux to access your Cisco devices.

Thanks

John

[moman62]

Do you use it like putty or secure crt? by just using the IP Address? or is it a different sign-on?

[johnd2310]

Hi,

Once you install the openssh-client, you go to a terminal and run ssh user@x.x.x.x to connect to you device.

Thanks

John

[moman62]

I get this error message:

Unable to negotiate with 10.10.22.5 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

[Seb Rupik]

Hi there,

As a sanity check confirm that the cipher is not in the configured allowed list:

ssh -Q cipher

To explicitly use the cipher, try the following:

ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -l <username> <ip_address>

cheers,

Seb.

[johnd2310]

Hi,

Your cisco device is using weak ciphers. You should try and upgrade the code on your Cisco device.Try connecting to the device using the following command:

ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 user@10.10.22.5

Thanks

John

[moman62]

ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 @Username@10.10.10.5

Unable to negotiate with 192.168.1.61 port 22: no matching cipher found. Their offer: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc

Results From ssh -Q cipher:

3des-cbc
aes128-cbc
aes192-cbc
aes256-cbc
rijndael-cbc@lysator.liu.se
aes128-ctr
aes192-ctr
aes256-ctr
aes128-gcm@openssh.com
aes256-gcm@openssh.com
chacha20-poly1305@openssh.com

[Seb Rupik · Accepted solution]

OK, try:

ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -c aes128-cbc -l <username> 10.10.10.5

[moman62]

Thank you! the solution worked for me!