Can't connect to a server via SSH (with my PC only)

Question

For some days I'm experiencing issues with SSH on my machine (I guess after having installed some softs that I don't remember... (sic))

It's very problematic as I use Git to work on some code projects with other people, pushing my work on a repository via SSH.

I'm 100 % sure the problem is coming from my computer (Linux Mint 16 cinnamon), because:

• From the same Internet connexion (same router, same IP), I can connect without any problem to the same server with another computer. Therefore, it's not a firewall problem coming from the router.

• The admin of the server doesn't see any issues that could create this concern, and everybody else has access as they should.

This is the error message Git tells me:

ssh: connect to host ******* port 22: Connection refused
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Result of command netstat -plant | grep :22

tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1248/sshd       
tcp6       0      0 :::22    

I was told that could be a problem with my iptables, and have tried to sudo iptables -X (and -F), with no luck. I have no idea how to manage this further...

EDIT:

As asked in the comments, I tried to run an ordinary SSH session in verbose mode. Here are the messages I have:

-$ ssh -v [email protected]
OpenSSH_6.2p2 Ubuntu-6ubuntu0.4, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to [email protected] [82.165.49.211] port 22.
debug1: connect to address 82.165.49.211 port 22: Connection refused
ssh: connect to host [email protected] port 22: Connection refused

Result of command ls -al /var/run/

total 52
drwxr-xr-x 25 root       root        820 jan 30 20:49 .
drwxr-xr-x 24 root       root       4096 oct 14 22:35 ..
-rw-r--r--  1 root       root          5 jan 30 20:49 acpid.pid
srw-rw-rw-  1 root       root          0 jan 30 20:49 acpid.socket
drwxr-xr-x  2 root       root         60 jan 30 20:49 apache2
drwxr-xr-x  2 avahi      avahi        80 jan 30 20:49 avahi-daemon
drwxr-xr-x  2 root       root         60 jan 30 20:49 console
drwxr-xr-x  2 root       root         60 jan 30 20:49 ConsoleKit
-rw-r--r--  1 root       root          5 jan 30 20:49 console-kit-daemon.pid
-rw-r--r--  1 root       root          5 jan 30 20:49 crond.pid
----------  1 root       root          0 jan 30 20:49 crond.reboot
drwxr-xr-x  3 root       lp          120 jan 30 20:49 cups
drwxr-xr-x  2 messagebus messagebus   80 jan 30 20:48 dbus
srw-rw-rw-  1 root       root          0 jan 30 20:49 gdm_socket
drwxr-xr-x  2 root       root         40 jan 30 20:49 initramfs
drwxrwxrwt  3 root       root         60 jan 30 20:49 lock
-rw-r--r--  1 root       root          5 jan 30 20:49 mdm.pid
-rw-r--r--  1 root       root        135 jan 30 20:48 motd
drwxr-xr-x  2 root       root         60 jan 30 20:48 mount
drwxr-xr-x  2 mysql      root         80 jan 30 20:49 mysqld
drwxr-xr-x  3 root       root        140 jan 30 20:49 network
drwxr-xr-x  2 root       root        100 jan 30 20:49 NetworkManager
-rw-r--r--  1 root       root          5 jan 30 20:49 pglcmd.wd.pid
-rw-r--r--  1 root       root          5 jan 30 20:49 pgld.pid
drwxr-xr-x  2 root       root         40 jan 30  2015 plymouth
drwxr-xr-x  4 root       root         80 jan 30 20:49 pm-utils
drwxr-xr-x  2 root       root         40 jan 30 20:49 pppconfig
drwxr-xr-x  3 root       root        100 jan 30 20:49 resolvconf
-rw-r--r--  1 root       root          4 jan 30 20:48 rsyslogd.pid
drwxr-xr-x  2 root       root        320 jan 30 20:49 samba
srw-rw-rw-  1 root       root          0 jan 30 20:48 sdp
drwxr-xr-x  2 root       root         60 jan 30 20:49 sendsigs.omit.d
drwxrwxrwt  2 root       root        140 jan 30 20:49 shm
drwxr-xr-x  6 root       root        120 jan 30 20:49 systemd
drwxr-xr-x  6 root       root        160 jan 30 20:49 udev
drwx------  2 root       root         40 jan 30 20:49 udisks2
-rw-r--r--  1 root       root          4 jan 30 20:48 upstart-file-bridge.pid
-rw-r--r--  1 root       root          4 jan 30 20:48 upstart-socket-bridge.pid
-rw-r--r--  1 root       root          4 jan 30 20:48 upstart-udev-bridge.pid
drwxr-xr-x  3 root       root         60 jan 30 20:49 user
-rw-rw-r--  1 root       utmp       3840 jan 30 20:50 utmp

Content of /etc/ssh/ssh_config (without "#" comments lines)

Host *
# (...)
SendEnv LANG LC_*
HashKnownHosts yes
GSSAPIAuthentication yes
GSSAPIDelegateCredentials no

Solution

I've finally found a way to fix the issue I had. I found this article about iptables. It helped me a lot to fix the issue.

The only thing I did is run the command

sudo iptables -F

Doing that has allowed me to push again on remote repositories and thus using ssh. But I had to save that.

For this I run this other command to make all the changements due to the previous command persistent

sudo apt-get update
sudo apt-get install iptables-persistent

I found that thanks the article linked previously. I rebooted in the meantime and everything is working correctly.

Comments

[devnull]

Have you tried disabling your firewall first and see if you can ssh? If it succeeds then it definitely is a bad firewall rule: sudo ufw disable

[Mark Plotnick]

The error message says uid=1000 pid=6098 comm="start ssh ", which indicates it was running as uid 1000. Try sudo service ssh restart.

[TheMeaningfulEngineer]

Can you test an ordinary ssh session with verbose on, to that server? ssh -v [email protected] use the server ip

[Azuk]

@DevNull - I disabled my firewall with the command you showed me but I'm still unable to push to the server.I just have a message telling " the firewall is stopped & disabled during the boot system".

[Azuk]

@MarkPlotnick I ran aswell your command to restart the ssh service, I got as answer this -> "stop: Unknown instance: ssh stop/pre-start, process 8957". I'm still unable to connect.

[Azuk]

@Alan Here is the result I got when trying to connect to the server with the -v parameter ssh -v theuser.onlinehome.fr OpenSSH_6.2p2 Ubuntu-6ubuntu0.4, OpenSSL 1.0.1e 11 Feb 2013 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug1: Connecting to theuser.onlinehome.fr [82.165.49.211] port 22. debug1: connect to address 82.165.49.211 port 22: Connection refused ssh: connect to host theuser.onlinehome.fr port 22: Connection refused

[devnull]

@Azuk Can you run this command and update your questions with the output ls -al /var/run/

[TheMeaningfulEngineer]

Try with maximum verbosity (-vvv)

[Azuk]

@DevNull It still doesn't work, with the first command I indeed get a process /usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session etc... It had the id of 2321, so I ran the command to kill it as root. I then restarted the SSH services. It returned top: Unknown instance: ssh stop/pre-start, process 4543 But that still doesn't work. However, there is something odd, after killing the PID and restarting the SSH services I ran again the command to see the SSH processes and the process still appear with the same orginal ID which is 2321.

[Azuk]

@Alan I tested with maximum verbosity and the output is exactly the same as one single -v parameter...

[TheMeaningfulEngineer]

It is possible that the server only has ssh enabled for git. Try getting the git to run ssh in verbose. (the link I posted)

[Azuk]

I added the config file as I didn't have one in my .ssh folder and put the code as shown in the link. It seems It doesn't work. Here is what I have when I run again the command with -vvv OpenSSH_6.2p2 Ubuntu-6ubuntu0.4, OpenSSL 1.0.1e 11 Feb 2013 debug1: Reading configuration data /home/geo/.ssh/config /home/geo/.ssh/config line 2: unsupported log level '(QUIET|FATAL|ERROR|INFO|VERBOSE|DEBUG|DEBUG1|DEBUG2|DEBUG3)

[Kenster]

Regarding the ps output, the netstat output, and the /var/run listing, are these listings from the computer you're trying to connect to, or the computer you're connecting from?

[Gilles 'SO- stop being evil']

Is the IP address correct? (You might have a stale DNS cache for some reason.) Is some option being applied through /etc/ssh/ssh_config or ~/.ssh/config? Post their content or try moving them out of the way.

[Azuk]

@Gilles, I edited my first post to put the outputs of the two config files you asked me. At first I had no config file in the ~/.ssh/config. I added this one as asked in a previous comment. You think I should move these files !?

[Kanwar Saad]

you are flushing all ip-table entries here. Instead of that just stop iptables by running "sudo service iptables stop"