title: Cisco SSH key exchange fails from Ubuntu 14.04 (Client DH key range mismatch)
body: <p>For some reason, I cannot SSH into a Cisco CSR1000v router from an Ubuntu 14.04 machine.</p>
  
  <p>Our Cisco firmware is;</p>
  
  <pre><code>Cisco IOS XE Software, Version 03.12.00.S - Standard Support Release
  Cisco IOS Software, CSR1000V Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 15.4(2)S, RELEASE SOFTWARE (fc2)
  </code></pre>
  
  <p>The server error being displayed is;</p>
  
  <pre><code>%SSH-3-DH_RANGE_FAIL: Client DH key range mismatch with maximum configured DH key on server
  </code></pre>
  
  <p>The client error being displayed is;</p>
  
  <pre><code>$ ssh -v admin@172.16.3.253
  OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
  debug1: Reading configuration data /etc/ssh/ssh_config
  debug1: /etc/ssh/ssh_config line 19: Applying options for *
  debug1: Connecting to 172.16.3.253 [172.16.3.253] port 22.
  debug1: Connection established.
  debug1: identity file /home/admin/.ssh/id_rsa type 1
  debug1: identity file /home/admin/.ssh/id_rsa-cert type -1
  debug1: identity file /home/admin/.ssh/id_dsa type -1
  debug1: identity file /home/admin/.ssh/id_dsa-cert type -1
  debug1: identity file /home/admin/.ssh/id_ecdsa type -1
  debug1: identity file /home/admin/.ssh/id_ecdsa-cert type -1
  debug1: identity file /home/admin/.ssh/id_ed25519 type -1
  debug1: identity file /home/admin/.ssh/id_ed25519-cert type -1
  debug1: Enabling compatibility mode for protocol 2.0
  debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
  debug1: Remote protocol version 2.0, remote software version Cisco-1.25
  debug1: no match: Cisco-1.25
  debug1: SSH2_MSG_KEXINIT sent
  debug1: SSH2_MSG_KEXINIT received
  debug1: kex: server-&gt;client aes128-ctr hmac-sha1 none
  debug1: kex: client-&gt;server aes128-ctr hmac-sha1 none
  debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024&lt;7680&lt;8192) sent
  debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
  Connection closed by 172.16.3.253
  </code></pre>