SSH "connection refused" on Raspberry pi - cannot find why

Question

I have the following problem SSH "connection refused". It would work fine, but while I am working on the SSH, I would get "connection refused" and would have to re-connect (which does not occur for good 5-10 minutes). I have tried everything (restart linux, restart ssh) yet still does not help. I've checked var/log as well but nothing helpful in there...

NOTE: Interesting note I found is, when I try ssh to my external ip(277...), it goes to black cmd screen, I close this and try my 192.168.0.13 address and it lets me sign in.. but short while, again connection refused... Of course if I open my server and sudo sshd restart, my ssh "connection refused" goes away...

My ssh port is opened at 23, and I have it set on modem/router as well

sudpi@raspberrypi:~$ sudo netstat -tlpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1817/apache2
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 2227/vsftpd
tcp 0 0 127.0.0.1:3350 0.0.0.0:* LISTEN 1784/xrdp-sesman
tcp 0 0 0.0.0.0:23 0.0.0.0:* LISTEN 3115/sshd
tcp 0 0 0.0.0.0:3389 0.0.0.0:* LISTEN 1781/xrdp
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 2397/mysqld

When I get disconnected, and log back in and check "WHO" I only see my previous connection, my root and the current connection

whopi@raspberrypi:~$ who 
pi tty1 2013年01月28日 09:20
pi pts/0 2013年01月28日 10:28 (192.168.0.12)
pi pts/1 2013年01月28日 10:32 (192.168.0.12)

This is what I have in my ssh_config that I have modified (SSH to 23 because rogers use 22...)

# Port 23
... 
#Keep my damn connection alive!
KeepAlive yes
ServerAliveInterval 60

This is what I get when I run arp-scan

pi@raspberrypi:/etc$ sudo arp-scan -I eth0 -l | grep 192.168.0.13
192.168.0.13 a0:6c:ec:ec:bb:5b (Unknown)

This part I found online that told me I should post the following two information

pi@raspberrypi:~$ ps afxu | grep sshd
root 2838 0.0 0.7 9800 3168 ? Ss 10:27 0:00 sshd: pi [priv] 
pi 2845 0.0 0.3 9800 1628 ? S 10:28 0:00 \_ sshd: pi@pt s/0
root 2854 0.0 0.7 9800 3168 ? Ss 10:32 0:00 sshd: pi [priv] 
pi 2861 0.0 0.3 9800 1628 ? S 10:32 0:00 \_ sshd: pi@pt s/1
root 2900 0.3 0.7 9800 3168 ? Ss 10:44 0:00 sshd: pi [priv] 
pi 2907 0.0 0.3 9800 1628 ? S 10:44 0:00 \_ sshd: pi@pt s/2
root 2934 0.0 0.2 6204 1060 ? Ss 10:45 0:00 /usr/sbin/sshd
root 2954 0.7 0.7 9800 3164 ? Ss 10:45 0:00 \_ sshd: pi [p riv]
pi 2961 0.1 0.3 9800 1624 ? S 10:46 0:00 \_ sshd: p i@pts/3
pi 2970 0.0 0.1 3536 796 pts/3 S+ 10:46 0:00 \_ grep sshd

EDIT: pi@raspberrypi:~$ ssh -vvv 192.168.0.13 (THIS might be long... Thank you Bart Friederichs)

pi@raspberrypi:~$ ssh -vvv 192.168.0.13 -p 23
OpenSSH_6.0p1 Debian-3, OpenSSL 1.0.1c 10 May 2012
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.0.13 [192.168.0.13] port 23.
debug1: Connection established.
debug1: SELinux support disabled
...
debug1: match: OpenSSH_6.0p1 Debian-3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.0p1 Debian-3
debug2: fd 3 setting O_NONBLOCK
debug3: put_host_port: [192.168.0.13]:23
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
...
debug1: Next authentication method: publickey
debug1: Trying private key: /var/www/.ssh/id_rsa
debug3: no such identity: /var/www/.ssh/id_rsa
debug1: Trying private key: /var/www/.ssh/id_dsa
debug3: no such identity: /var/www/.ssh/id_dsa
debug1: Trying private key: /var/www/.ssh/id_ecdsa
debug3: no such identity: /var/www/.ssh/id_ecdsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
[email protected]'s password: - I TYPED PASSWORD -
...
debug2: channel_input_status_confirm: type 99 id 0
debug2: PTY allocation request accepted on channel 0
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Linux raspberrypi 3.6.11+ #350 PREEMPT Mon Jan 7 21:51:11 GMT 2013 armv6l

• Bruno: Run netstat -tlpn as root (or with sudo) if you want to see the program names/PIDs. Moving SSH from its default port doesn't seem to be a good idea if you're not sufficiently familiar with Linux administration.
• Pipe: Lines started with # are comments, so in the line you specify the port 23 you have the # before, it will not be processed, and therefore it will use standard port (22). You can also have something in /etc/hosts.allow or /etc/hosts.deny controlling who can connect to sshd. Do you have checked if you don't have collision with ip address in your network?

Answer 1

Your sshd is listening on port 23, yet you are connecting to port 22 (ssh's default).

Try this:

 pi@raspberrypi:~$ ssh -vvv 192.168.0.13 -p 23

A "connection refused" error means the TCP layer in the kernel is not accepting any connections on that port. It has nothing to do with keeping alive or anything.

Also, you are using arp to find out stuff, but a better tool would be nmap. arp only tells you if the IP is in your broadcast domain, not if any ports are open.

• Taehoon A Kim: Hello, Thank you for your reply, I've tried pi@raspberrypi:~$ nmap -bash: nmap: command not found... would I need to install it? and is there such for raspberry? Also thank you for the correction, I've edited with -p 23, but It doesn't have anything that looks out of place...
• Bart Friederichs: nmap isn't really needed, just a handy tool. The update you made seems to have made it work?

Answer 2

Quoting the documentation:

As of the November 2016 release, Raspbian has the SSH server disabled by default. You will have to enable it manually.

To enable SSH on machines through console:

Enter sudo raspi-config in the terminal, first select advanced options, then navigate to ssh, press Enter and select Enable or disable ssh server.

To enable SSH for headless machines:

For headless setup, SSH can be enabled by placing a file named ssh, without any extension, onto the boot partition of the SD card.

---

Copy-pasted from @techraf's answer in this related question: SSH not working with fresh install.

• Darth Vader: Whilst this might technically answer the question, I'm not sure techraf is going to be happy that you have just copy and pasted their answer. However, if you asked for their permission before making this post that would be different.
• goldilocks: Part of the "terms of service" (sec. 3) is that contributions here are considered to have a Creative Commons Attribution ShareAlike license, and this re-appropriation is within those terms. However, it's not much of an answer here since it is pretty clear in the question that sshd is running, and the issue was prior to 2016.
• Delgan: @DarthVader I posted this as a community answer, properly crediting the author, I thought it would be enough.
• Delgan: @goldilocks As you may have guessed, this question comes on the top of Google search results about ssh connexion refused for Raspberry Pi. I believed this would help people to figure out faster what could be the issue.
• R2RT: On the current newest (Raspbian Stretch) SSH configuration is located under 5) Interfacing Options -> P2) SSH

Answer 3

I had the same problem this morning, and got it fixed by removing and installing openssh-server:

sudo apt-get remove openssh-server 
sudo apt-get install openssh-server

• NULL: Hello and Welcome to Stack Exchange! Please consider adding a more in depth explanation for the benefit of future readers.

Answer 4

I had the same problem and my solution was to disable and uninstall iptables.

run those commands:

(as sudoer)

iptables -F iptables -X iptables -t nat -F iptables -t nat -X iptables -t mangle -F iptables -t mangle -X iptables -P INPUT ACCEPT iptables -P OUTPUT ACCEPT iptables -P FORWARD ACCEPT

sudo apt-get remove --purge iptables

Answer 5

For me the following worked: went to /etc/ssh/ssh_config and /etc/ssh/sshd_config and then allowed access with no password.

Restarted the service and voilà, working!

Answer 6

Updating Delgan's answer for Raspberry pi 3, RASPBIAN JESSIE WITH PIXEL OS

In terminal

sudo raspi-config 

Select Interfacing options -> SSH. Press Enter and select Enable or disable ssh server

Answer 7

I am not sure if my tip is going to be helpful. I had the same problem and I am new to linux world. After reading Raspberry Pi documentation I found that the issue is in Pi Configuration where SSH was Disabled.

Click on Raspberry Pi Menu --> Preferences --> Launch Raspberry Pi Configuration Navigate to the Interfaces tab Select Enabled next to SSH Click OK This resolved my issue. Please try and let me know.

Answer 8

with

sudpi@raspberrypi:~$ sudo netstat -tlpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1817/apache2
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 2227/vsftpd
tcp 0 0 127.0.0.1:3350 0.0.0.0:* LISTEN 1784/xrdp-sesman
tcp 0 0 0.0.0.0:23 0.0.0.0:* LISTEN 3115/sshd
tcp 0 0 0.0.0.0:3389 0.0.0.0:* LISTEN 1781/xrdp
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 2397/mysqld

• Morgan Courbet: It is a good start to check what the problem is, but not enough to answer the question :-(

Answer 9

I had the same problem but is was resolved after I ran the command

sudo apt-get remove --purge iptables. and switching off the wireless connectivity.

Answer 10

There are 2 configuration files /etc/ssh/ssh_config and /etc/ssh/sshd_config

Change the port from 22 to whatever you want in both files.

restart the service sudo service ssh restart

• Bex: But... that will only work if your ssh:ing into the same machine. What would be the point of that?