sudo apt-get install openssh-server  - habilitar ssh 

sudo systemctl enable ssh. 

Resolução de mismatching key 

diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1

inserir a linha no arquivo ssh_conf

KexAlgorithms diffie-hellman-group1-sha1,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1

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

    KexAlgorithms diffie-hellman-group1-sha1,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1 

TUNNEL GRE LINUX 

ip link add gre1 type gretap remote 192.168.1.2 local 192.168.1.51 ip link set dev gre1 up

ip link set dev gre1 up

ifconfig gre1 172.16.2.2/24