SSH is not working in Ubuntu /Windows CMD prompt

[Cisconew]

Hi,

I am able to SSH my Router (Physical Device/1841) via Putty terminal.

But not able do it through Ubuntu terminal/Windows CMD prompt.

Please find below Show SSH output for reference.

Router-1841#sh ssh
Connection Version Mode Encryption Hmac State Username
0 2.0 IN aes256-cbc hmac-sha1 Session started jason
0 2.0 OUT aes256-cbc hmac-sha1 Session started jason
%No SSHv1 server connections running.

Also, please find below the ssh output from ubuntu terminal.

$ ssh username@192.168.1.100
Unable to negotiate with 192.168.1.100 port 22: no matching key exchange method found. Their offer: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1

Any suggestion?

Thanks in advance.

[Georg Pauwen]

Hello,

how did you configure the SSH client ? You need to include the DH sha1 in the configuration file of your client. Post the content of the client configuration file...

[Cisconew]

Hi,

Please find below the ubuntu ssh config file:

$ cat /etc/ssh/ssh_config

# This is the ssh client system-wide configuration file. See
# ssh_config(5) for more information. This file provides defaults for
# users, and the values can be changed in per-user configuration files
# or on the command line.

# Configuration data is parsed as follows:
# 1. command line options
# 2. user-specific file
# 3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.

# Site-wide defaults for some commonly used options. For a comprehensive
# list of available options, their meanings and defaults, please see the
# ssh_config(5) man page.

Include /etc/ssh/ssh_config.d/*.conf

Host *
# ForwardAgent no
# ForwardX11 no
# ForwardX11Trusted yes
# PasswordAuthentication yes
# HostbasedAuthentication no
# GSSAPIAuthentication no
# GSSAPIDelegateCredentials no
# GSSAPIKeyExchange no
# GSSAPITrustDNS no
# BatchMode no
# CheckHostIP yes
# AddressFamily any
# ConnectTimeout 0
# StrictHostKeyChecking ask
# IdentityFile ~/.ssh/id_rsa
# IdentityFile ~/.ssh/id_dsa
# IdentityFile ~/.ssh/id_ecdsa
# IdentityFile ~/.ssh/id_ed25519
# Port 22
# Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc
# MACs hmac-md5,hmac-sha1,umac-64@openssh.com
# EscapeChar ~
# Tunnel no
# TunnelDevice any:any
# PermitLocalCommand no
# VisualHostKey no
# ProxyCommand ssh -q -W %h:%p gateway.example.com
# RekeyLimit 1G 1h
SendEnv LANG LC_*
HashKnownHosts yes
GSSAPIAuthentication yes

[Georg Pauwen]

Hello,

you need to add the line below to your SSH config file:

KexAlgorithms +diffie-hellman-group1-sha1

[Cisconew · Accepted solution]

Hi,

I have added the below to the config file along with one you have given.

Ciphers aes256-cbc,aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc

Now it is working. Thanks