Then I would guess leaving it blank would be the way to go?
Yes. Not quite there yet, but that got me further along the road (so to speak). Now I'm getting the following "Unable to negotiate with [my public facing ip] 93.xxx.xxx.xxx port xx: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1." Re-entering the command with '-vvv' produces a long output, which I'm going to paste further down, but before I do that, let me just fill you in on what I did initially after the first basic error message. I put it into a Google search and results (found here
https://www.openssh.com/legacy.html) seem to suggest that my OpenSSH package needs to be updated, that I could bypass the restriction but that that wouldn't be completely secure, exposing me to the so-called "Logjam attack". I began researching how to update my OpenSSH, but to be honest, whether this means my MacBook or the Freenas server isn't clear (to me). I'm assuming it's my Mac because that's what's doing the ssh negotiation. I then discovered that this wasn't easy and had to install Homebrew to achieve it. (NOTE: I can't remember why this was necessary but that's what I started to do.) After much effort and cussin' and swearin', I finally managed to install Homebrew - there were problems with the installation in relation to PATH which I eventually managed to resolve - but I'm now stuck at another stage. And this has cause me to pause. I need to make sure that this update is absolutely necessary by checking if anyone reading this has come across this problem? Do I need to be uneasy about the Logjam attack? Should I be really worried, given the spate of ransomware attacks so recently in the news?
Back to the error output. Will yet again appreciate any thoughts or suggestions. Note that ssh within the LAN still works perfectly, so I don't understand line 9 which states "debug1: key_load_public: No such file or directory". This is what I have (minus certain obvious bits of information irrelevant to this discussion):
OpenSSH_7.5p1, OpenSSL 1.0.2k 26 Jan 2017
debug1: Reading configuration data /Users/Zigbook/.ssh/config
debug1: Reading configuration data /usr/local/etc/ssh/ssh_config
debug2: resolving "93.xxx.xxx.xxx” port xx
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 93.xxx.xxx.xxx [93.xxx.xxx.xxx] port xx.
debug1: Connection established.
debug1: identity file /Users/Zigbook/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/Zigbook/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.5
debug1: Remote protocol version 2.0, remote software version dropbear_0.50
debug1: no match: dropbear_0.50
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 93.xxx.xxx.xxx:xx as 'ziggy'
debug3: hostkeys_foreach: reading file "/Users/Zigbook/.ssh/known_hosts"
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms:
ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc:
chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc:
umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,ssh-dss
debug2: ciphers ctos: 3des-cbc
debug2: ciphers stoc: 3des-cbc
debug2: MACs ctos: hmac-sha1,hmac-md5
debug2: MACs stoc: hmac-sha1,hmac-md5
debug2: compression ctos: zlib,none
debug2: compression stoc: zlib,none
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: (no match)
Unable to negotiate with 93.xxx.xxx.xxx port xx: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1