user@localhost ~ $ ssh -v admin@172.16.1.2
OpenSSH_7.1p1-hpn14v9, OpenSSL 1.0.2d 9 Jul 2015
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Connecting to 172.16.1.2 [172.16.1.2].
debug1: Connection established.
debug1: identity file /home/alex/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/alex/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.1p1-hpn14v9
debug1: Remote protocol version 2.0, remote software version DLINK Corp. SSH server ver 1.00.000
debug1: no match: DLINK Corp. SSH server ver 1.00.000
debug1: Authenticating to 172.16.1.2 as 'admin'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: AUTH STATE IS 0
debug1: REQUESTED ENC.NAME is 'aes128-cbc'
debug1: kex: server->client aes128-cbc hmac-sha1 none
debug1: REQUESTED ENC.NAME is 'aes128-cbc'
debug1: kex: client->server aes128-cbc hmac-sha1 none
Unable to negotiate with 172.16.1.2: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

DES-3200-28:admin#show config current_config include "ssh"
Command: show config current_config include "ssh"
config ssh algorithm 3DES enable
config ssh algorithm AES128 enable
config ssh algorithm AES192 enable
config ssh algorithm AES256 enable
config ssh algorithm arcfour enable
config ssh algorithm blowfish enable
config ssh algorithm cast128 enable
config ssh algorithm twofish128 enable
config ssh algorithm twofish192 enable
config ssh algorithm twofish256 enable
config ssh algorithm MD5 enable
config ssh algorithm SHA1 enable
config ssh algorithm RSA enable
config ssh algorithm DSA enable
config ssh authmode password enable
config ssh authmode publickey enable
config ssh authmode hostbased enable
config ssh server maxsession 8
config ssh server contimeout 600
config ssh server authfail 2
config ssh server rekey never
config ssh server port 22                                                   
config ssh user admin authmode password
config ssh publickey bypass_login_screen state disable
enable ssh
config authen application ssh login default
config authen application ssh enable default