UbuntuホストからCiscoルータにログインしようとしたら蹴られた件 ref: http://qiita.com/skomma/items/f9085dfb369e0aadb97f

file0.txt

$ ssh xxx.xxx.xxx.xxx
Connection closed by xxx.xxx.xxx.xxx

file1.txt

1017854: May  6 15:32:48.673 JST: SSH2 1:  Invalid modulus length

file2.txt

1017830: May  6 15:32:48.637 JST: SSH1: starting SSH control process
1017831: May  6 15:32:48.637 JST: SSH1: sent protocol version id SSH-2.0-Cisco-1.25
1017832: May  6 15:32:48.641 JST: SSH1: protocol version id is - SSH-2.0-OpenSSH_6.6p1 Ubuntu-2ubuntu1
1017833: May  6 15:32:48.641 JST: SSH2 1: send:packet of  length 344 (length also includes padlen of 5)
1017834: May  6 15:32:48.641 JST: SSH2 1: SSH2_MSG_KEXINIT sent
1017835: May  6 15:32:48.657 JST: SSH2 1: ssh_receive: 536 bytes received
1017836: May  6 15:32:48.657 JST: SSH2 1: input: total packet length of 1792 bytes
1017837: May  6 15:32:48.657 JST: SSH2 1: partial packet length(block size)8 bytes,needed 1784 bytes,
               maclen 0
1017838: May  6 15:32:48.657 JST: SSH2 1: ssh_receive: 536 bytes received
1017839: May  6 15:32:48.657 JST: SSH2 1: partial packet length(block size)8 bytes,needed 1784 bytes,
               maclen 0
1017840: May  6 15:32:48.657 JST: SSH2 1: ssh_receive: 536 bytes received
1017841: May  6 15:32:48.657 JST: SSH2 1: partial packet length(block size)8 bytes,needed 1784 bytes,
               maclen 0
1017842: May  6 15:32:48.657 JST: SSH2 1: ssh_receive: 184 bytes received
1017843: May  6 15:32:48.657 JST: SSH2 1: partial packet length(block size)8 bytes,needed 1784 bytes,
               maclen 0
1017844: May  6 15:32:48.657 JST: SSH2 1: input: padlength 10 bytes
1017845: May  6 15:32:48.661 JST: SSH2 1: SSH2_MSG_KEXINIT received
1017846: May  6 15:32:48.661 JST: SSH2:kex: client->server enc:aes128-cbc mac:hmac-md5
1017847: May  6 15:32:48.661 JST: SSH2:kex: server->client enc:aes128-cbc mac:hmac-md5
1017848: May  6 15:32:48.673 JST: SSH2 1: ssh_receive: 24 bytes received
1017849: May  6 15:32:48.673 JST: SSH2 1: input: total packet length of 24 bytes
1017850: May  6 15:32:48.673 JST: SSH2 1: partial packet length(block size)8 bytes,needed 16 bytes,
               maclen 0
1017851: May  6 15:32:48.673 JST: SSH2 1: input: padlength 6 bytes
1017852: May  6 15:32:48.673 JST: SSH2 1: SSH2_MSG_KEX_DH_GEX_REQUEST received
1017853: May  6 15:32:48.673 JST: SSH2 1: Range sent by client is - 1024 < 3072 < 8192
1017854: May  6 15:32:48.673 JST: SSH2 1:  Invalid modulus length
1017855: May  6 15:32:48.773 JST: SSH1: Session disconnected - error 0x00

file3.txt

cisco886va(config)#ip ssh dh min size 4096

file4.txt

$ ssh -o KexAlgorithms=diffie-hellman-group14-sha1 xxx.xxx.xxx.xxx
Password:

Router>exit

file5.txt

Host hoge
  HostName xxx.xxx.xxx.xxx
  KexAlgorithms diffie-hellman-group14-sha1