My LAN comprises a background calculator running Linux ( Debian Wheezy ), a MacBook with OS X Mavericks, and a modem-router ; ssh with Linux host and OS X client functions well – no problems connecting from client to host .
additionally, I ’ ve tried to implement the reversion – Linux calculator besides becoming a customer and the OS X calculator besides becoming a horde. But attempting to ssh from Linux client to OS X host results in

ssh_exchange_identification: Connection closed by remote host

This happens regardless of whether the Mac firewall is turned on or off .
I ’ ve hear numerous solutions suggested by google searches, including at :

record link description hera insert radio link description here
( The system did n’t allow me to post any more links. )
I ’ megabyte reasonably sure that file ownerships, permissions, configurations are compensate .
The lapp port, say 1234, is configured for ssh on each calculator as both host and node ; netstat commands from both computers indicate that port 1234 is listened to. Neither DenyHosts nor fail2ban is installed .
On the Linux node, /var/log/auth.log doesn ’ thymine give any relevant messages .
Telneting from client to host gives

Connection closed by foreign host.

On the OS X host, at the time of an attempted ssh association :
/var/log/appfirewall.log shows
MacBook.local socketfilterfw[636] : sshd-keygen-wrapper: Allow TCP CONNECT (in:1 out:0 )
/var/log/system.log shows

MacBook.local com.apple.preference.security.remoteservice[662]: nsc_smb XPC: handle_event error : < Connection invalid >

It seems that the problem resides with the OS X horde and that the cardinal to solving it could be in these messages, but I ’ ve been ineffective to find utilitarian information .
On the MacBook, System Preferences > Security & Privacy > Firewall > Firewall Options, “ Remote Login ( SSH ) ” and “ sshd-keygen-wrapper ” are set to “ Allow incoming connections ”.

“ Remote Login ” is enabled in System Preferences > Sharing .
What could be causing the ssh association trouble and how to solve it ?
Additional Information Since Initial Post
Thanks for the replies, but I had already done everything outlined in the links, had Remote Login on with my user name ( alex ) as a exploiter, and restarted ssh on both computers after every change concerning ssh followed by rebooting both computers. Have besides reinstalled ssh respective times on the Linux calculator, and generated newly keys several times on both computers .
possibly I should have clarified that in ssh_config for both clients

PasswordAuthentication no
PubkeyAuthentication yes

here is the request end product from the OS X horde : ( not certain how useful it is because I had changed the ssh port from the default 22, to say 1234 )

MacBook:~ alex$ ssh -vvv localhost
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug2: ssh_connect: needpriv 0
debug1: Connecting to localhost [::1] port 22.
debug1: connect to address ::1 port 22: Connection refused
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: connect to address 127.0.0.1 port 22: Connection refused
debug1: Connecting to localhost [fe80::1%lo0] port 22.
debug1: connect to address fe80::1%lo0 port 22: Connection refused
ssh: connect to host localhost port 22: Connection refused

Additional clarifying information :

MacBook:~ alex$ ssh -vvv -p 1234 localhost
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug2: ssh_connect: needpriv 0
debug1: Connecting to localhost [::1] port 1234.
debug1: connect to address ::1 port 1234: Connection refused
debug1: Connecting to localhost [127.0.0.1] port 1234.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/Users/alex/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /Users/alex/.ssh/id_rsa type 1
debug1: identity file /Users/alex/.ssh/id_rsa-cert type -1
debug1: identity file /Users/alex/.ssh/id_dsa type -1
debug1: identity file /Users/alex/.ssh/id_dsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
ssh_exchange_identification: Connection closed by remote host
MacBook:~ alex$ 

Requested output from the Linux customer :

alex@desktop:~$ ssh -v alex@MacBook.local
OpenSSH_6.0p1 Debian-4+deb7u2, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 20: Applying options for *
debug1: /etc/ssh/ssh_config line 102: Applying options for *
debug1: Connecting to MacBook.local [192.168.0.3] port 1234.
debug1: Connection established.
debug1: identity file /home/alex/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/alex/.ssh/id_rsa-cert type -1
ssh_exchange_identification: Connection closed by remote host
alex@desktop:~$ 

After going to a lot of feat to get ssh working with Linux as host and OS X as customer, I figured that doing the change by reversal would be relatively simpleton. Maybe it is, but not so far ! far help would be a lot appreciated .
Lars

MacBook:~ alex$ sudo sshd -t
Password:
/etc/sshd_config: No such file or directory
MacBook:~ alex$

The sshd_config file is in /private/etc/ssh, as is ssh_config and the ssh_host key files .
Problem Solved

I placed a copy of sshd_config into /private/etc and did sudo sshd -t. The output gave format errors suggesting style errors with a citation to rtf. The baptismal font was Times. I had copied the file from the Linux computer and in the march the baptismal font changed from plain textbook .
I changed the sshd_config file in /private/etc/ssh to plain textbook, toggled “ Remote Login ” in System Preferences > Sharing on the Mac, issued the ssh command from the Linux node, and was able to connect to the OS X host for the first time .
I had n’t come across the sshd -t instruction before, so thank Lars for bringing it to my attention and pointing me in the right direction. The solution was indeed simple, but identifying it was n’t .

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