ssh failure with MACOS High Sierra

I'm no network expert and this maybe a totally different issue, but I just helped a friend over the phone with what sounds like the same or similar problem. We struggling over the phone for about 15min. (dumb helping dumber) until I had him open and explain what he was seeing in the Network Preference Panel.

What happened to him was that the service order had switch from Ethernet to Wi-Fi when he disconnected the Ethernet cable to paint... Which make sense because both Services were turned ON.. The problem was, that for some reason it did not switch the Service Order back to Ethernet once the Ethernet connection was restored.

Long story short, go to your: Apple > System Preferences > Network setting and check to see if the Ethernet Service is connected and set as first in the Service order list.

If it is not,

click the cog on the Network preference panel > select "Set Service Order" and move Ethernet to the top.

or.... optionally if Wi Fi is not needed, turn it off which should force it back onto the Ethernet connection.

I also have this type of issue where i cannot access my switches on site but one access granted on some and not all remotely, this all started late last year, before this i could remote into any switch on or off site, teaks to add

1. HostkeyAlgorithms ssh-dss,ssh-rsa
2. KexAlgorithms +diffie-hellman-group1-sha1

# $OpenBSD: ssh_config,v 1.33 2017/05/07 23:12:57 djm Exp $

# This is the ssh client system-wide configuration file. See

# ssh_config(5) for more information. This file provides defaults for

# users, and the values can be changed in per-user configuration files

# or on the command line.

# Configuration data is parsed as follows:

# 1. command line options

# 2. user-specific file

# 3. system-wide file

# Any configuration value is only changed the first time it is set.

# Thus, host-specific definitions should be at the beginning of the

# configuration file, and defaults at the end.

# Site-wide defaults for some commonly used options. For a comprehensive

# list of available options, their meanings and defaults, please see the

# ssh_config(5) man page.

# Host *

# ForwardAgent no

# ForwardX11 no

# RhostsRSAAuthentication no

# RSAAuthentication yes

# PasswordAuthentication yes

# HostbasedAuthentication no

# GSSAPIAuthentication no

# GSSAPIDelegateCredentials no

# BatchMode no

# CheckHostIP yes

# AddressFamily any

# ConnectTimeout 0

# StrictHostKeyChecking ask

# IdentityFile ~/.ssh/identity

# IdentityFile ~/.ssh/id_rsa

# IdentityFile ~/.ssh/id_dsa

# IdentityFile ~/.ssh/id_ecdsa

# IdentityFile ~/.ssh/id_ed25519

# Port 22

# Protocol 2

# Cipher 3des

# Ciphers aes128-cbc,3des-cbc,blowfish-cbc

# Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc

# MACs hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com

# EscapeChar ~

# Tunnel no

# TunnelDevice any:any

# PermitLocalCommand no

# VisualHostKey no

# ProxyCommand ssh -q -W %h:%p gateway.example.com

# RekeyLimit 1G 1h

HostkeyAlgorithms ssh-dss,ssh-rsa

KexAlgorithms +diffie-hellman-group1-sha1

^G Get Help ^O WriteOut ^R Read File ^Y Prev Page ^K Cut Text ^C Cur Pos

^X Exit ^J Justify ^W Where Is ^V Next Page ^U UnCut Text ^T To Spell

Does not help, this worked perfeearly last year, Apple or anybody please guide me into resolving this issue.

Please note i am a newbie when it comes to MACOS

Kind regards

Phantumph

ssh connection requires advance configuration with System Preferences > Sharing > Remote login or your server-equivalent software.

There have been changes to the communication software in High Sierra and sharing by AFP is no longer supported, only SMB. There may be other unintended consequences as well.

Consider posting again on the MacOS server section of the forums.

Does your server expect the usual password, or does it require a certificate instead?